Silicon Based PV Cells

Silicon Based PV Cells
CHAPTER 2 – SILICON BASED PV CELLS 2 2.1 Doping Procedure of Silicon based PV Cells A
Silicon solar PV Cell is a device which is made up of semiconductor materials that produce
electricity when exposed to light energy. [1] The doping process of a Silicon based PV Cell works
by the photovoltaic material converting the light energy, photons, it absorbs into electrical energy.
[1] Light (Photon) Energy ––––––– Electrical Energy Using a doping process, a p–n junction is
created in silicon as shown below: From the image above the photons, light energy, prompt the
electrons flowing from the n–junction to the p–junction creating an electric current flow. [1] This is
highlighted below: The process of doping involves the addition of atoms with different number of
electrons so it creates an unbalanced number of electrons on the material that is being doped, in this
case Silicon. [1] The material being doped, in this case Silicon will carry a negative charge if the
base material absorbs excessive electrons. However, if the base material, Silicon, absorbs to little
electrons then the material will carry a positive charge. [1] To achieve a doped material, using
Silicon then there are 2 methods: Ion implantation of diffusion. These methods are carried out using
Boron (B) to form a positively charged doped material and Arsenide (As) or Phosphorus (P) to form
a negatively charged doped material. This is shown below: Ion Implantation can be achieved at
room temperature for
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Black Phosphorus Research Paper
Black Phosphorus was discovered in 1914. There was little known about it when it was first
discovered but that has changed in the past few decades. Researchers are looking into using black
phosphorus as a semiconductor, in electronics, optics, and LEDs. Many factors are to be considered
when thinking of using black phosphorus as a semiconductor, the cost, if large–scale synthesis is
possible while to being to complicated or expensive. Black Phosphorus has the potential to be a
great semiconductor because of its large tunable band gap. These are qualities that are wanted for
semiconductors however there needs to be further studies regarding black phosphorus to gain a
better understanding. Black phosphorus has many benefits and flaws compared ... Show more
content on Helpwriting.net ...
Researchers talk about black phosphori first synthesis in 1914, cost, how it is made, why
semiconductors are important, and how they work. There needs to be more done on black
phosphorus and black phosphorus as semiconductors. There are still a lot of discoveries to be made;
black phosphorus needs to be made stable in atmospheric conditions, cost effective, and have a high
yield. When these obstacles have been overcome, black phosphorus should be ready for testing in
electronic devices. Research involving black phosphorus has increased in popularity in the past 5
years. Black Phosphorus has a long way to go before devices with it in them will be on the market
but in the future there is a good change that there will be phones, computers, tablets and more that
have black phosphorus

The Structure Of Polypyrrole
The structure of polypyrrole consists of long conjugated polymer backbone as shown in Fig. 1.2b.
The polymer has resonance structures that resemble aromatic or quinoid forms. In this neutral state
the polymer is not conducting and it conducts only when it is oxidised. Polypyrrole is an insulator
but its oxidized derivatives are good conductors. The Conductivity ranges from 2 to 100 S/cm. The
charge associated with the oxidised state is typically delocalised over several units and can form a
radical cation (polaron) or a dication (bipolaron).
Polypyrrole is poorly crystalline, with crystalline regions randomly oriented and the polymer chains
lying with the pyrrole rings coplanar to the surface . Actually polypyrrole obtained so far ... Show
more content on Helpwriting.net ...
When the polymer is doped partially, islands of conducting material are developed, which are
oxidized sites on the polymer chain. A small percentage of the sites form a network, yielding a small
, finite DC conductivity. Hopping of charge carriers between favourable sites accounts for AC
conductivity. Thus the conductivity is a combination of frequency dependent AC conductivity and
DC conductivity. At higher level of doping, an increase in the network density through the polymer
chain results in elimination of number of isolated sites which give rise to AC conductivity. So at the
limit of very high doping the number of isolated sites is less and the DC conductivity dominates the
total conductivity.

Application Of Flexible All Graphite Paper Based Field...
Flexible All Graphite Paper based Field Effect Transistor for motion detection using strain sensing
Srinivasulu Kanaparthi, Sushmee Badhulika*
Department of Electrical Engineering, Indian Institute of Technology Hyderabad, Hyderabad,
502285, India.
*Corresponding author: E–mail: sbadh@iith.ac.in; Telephone: 040–23018443; Fax: 04023016032
Abstract
Here we report the fabrication of a flexible all carbon field effect transistor (FET) using a low cost,
recyclable and biodegradable cellulose paper as both substrate as well as dielectric and pencil
graphite as source, drain, channel and gate without using any other expensive, toxic or non–
biodegradable materials. The electron and hole mobility's of FET are observed to be 180 and 200
cm2v–1s–1 respectively which are comparable to the recently reported values of paper FET with
polymer dielectric and cellulose composite dielectrics. The FET was utilized as a strain sensor
which shows good sensitivity for low strains of both tensile and compressive type. The mobility of
the FET increases with increase in compressive strain and decreases with increase in tensile strain.
The sensitivity of the FET sensor increases with the increase in the gate voltage.
HERE YOU CAN MAKE A COMMENT ON HOW THIS STRAIN SENSOR IS BETTER THAN
SILICON STRAIN SENSORS IN PERFORMANCE.
Further we investigated the performance of the sensor by integrating it with hand gloves to detect
human motion. The results obtained indicate that the sensor can be utilized

Essay On Spin Field Effect Transistor
Spin is one of the most intriguing quantum properties carried by elementary particles. Incorporation
of electron spin into the operation of semiconductor devices enables novel functionalities and
increased performance for information processing and metrology. (–– removed HTML ––) (––
removed HTML ––) 1,2 (–– removed HTML ––) (–– removed HTML ––) Among the most
promising spin–based semiconductor devices is the spin field effect transistor (spinFET), (––
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considered a future candidate for high performance digital computing and memory with ultralow
energy needs. (–– removed HTML ––) (–– removed HTML ––) 4 (–– removed HTML ––) (––
removed HTML ––) (–– ... Show more content on Helpwriting.net ...
(–– removed HTML ––) (–– removed HTML ––) 9 (–– removed HTML ––) (–– removed HTML
––) Recognizing spin dephasing in a 2D channel as a limiting factor for a spinFET, it was proposed
in Ref. (–– removed HTML ––) 10 (–– removed HTML ––) to eliminate dephasing by tuning the
Rashba and Dresselhaus couplings such that the effects of spin orbit coupling are effectively
canceled. The model becomes then analytically solvable and there is no dephasing. Although the
tuning of Rashba and Dresselhaus coupling has been demonstrated experimentally, (–– removed
HTML ––) (–– removed HTML ––) 11 (–– removed HTML ––) (–– removed HTML ––) these
experiments involved complex structures of multiple quantum wells, not compatible with typical
III–V 2D channel FETs, for which the Rashba effect is generally recognized as dominant over the
Dresselhaus coupling. (–– removed HTML ––) (–– removed HTML ––) 5 (–– removed HTML ––)
(–– removed HTML ––) (–– removed HTML ––) (–– removed HTML ––) The objective of this
paper is to study the non–equilibrium spin transport in a 25 nm gate length In (–– removed HTML
––) 0.3 (–– removed HTML ––) Ga (–– removed HTML ––) 0.7 (–– removed HTML ––) As field–
effect transistor (FET) as an example of a realistic device, the structure of which is shown in Fig.
(–– removed HTML ––) 1 (–– removed HTML ––) . The study is carried out by

Microelectromechanical Systems (MEMS) are systems that are...
Microelectromechanical Systems (MEMS) are systems that are designed on a micro metre scale and
have become more popular as the demand for devices to get smaller has increased. The main uses of
these systems are for sensors, such as accelerometers and gyroscopes and other such devices like
microscopy and inkjet nozzles for example. There are many materials that can be used for MEMS as
the cost of the material is almost eradicated due to the micro size of the systems being produced.
This brings materials such as gold, platinum and diamond can be used, as these materials have some
properties which are very desirable for a MEM systems. The most common material that is currently
used in MEMS is silicon and silicon based compounds as they ... Show more content on
Helpwriting.net ...
The piezoresistivity properties of diamond allow it to be used for a variety of applications at
temperatures of up to 700oC . Also diamond films can actually be used as the active sensor layer
themselves in certain situations . This has been found useful for strain gauges and accelerometers as
well as other areas. It is due to the piezoresistive gauge factor of diamond to be between 70–4000
and remains as such even at high temperatures. Another advantage of using diamond in these
situations is that because its elastic modulus is much greater than other materials that would be used
such as Silicon or silicon based compounds the diamond films can operate at much higher
frequencies. Although it has been believed that only polycrystalline materials have these
piezoresistive properties, in recent times the same properties have been found in amorphous films of
both silicon and diamond.
As devices get smaller the surface to volume ratio increase dramatically down to the micrometre
scale which means that at these levels of design the surface phenomena become more important.
The forces which create these surface phenomena such as Van der Waal's capillary and local shear
forces due to the viscosity become the main factors at a

Synthesis and Characterization of Pb(S, Se)Thin Films.
Studies on chemically deposited Pb(S,Se) thin films J. D. Chaudhari *, R.D. Chaudhari * *, Dr. R.
H. Bari + Department of Physics, G. D. M. Arts, K. R. N. Commerce & M. D. Science College,
Jamner.Pin – 424 206 Abstract : Thin films of Pb(S,Se) [lead sulfoselenide] have been prepared on
glass substrate at 50°C by simple chemical bath deposition technique. The starting materials used
for deposition were lead acetate, tri–sodium citrate, sodium sulphite and elemental selenium.
Ammonium hydroxide solution was used to adjust pH of the bath. In order to obtain good quality
thin films, time, deposition temperature and pH of the solution were optimized and they are found to
be 1 hour, 50°C and 10 respectively. ... Show more content on Helpwriting.net ...
Tri–sodium citrate was used as complexing agent. Ammonium hydroxide solution was used to
adjust pH of the reaction mixture. All the chemicals used were of AR grade. Good quality films
obtained for optimized time, temperature of deposition and pH of solution of 1hour, 50o C and 10
respectively. The process involved the reaction of pb2+, S2– & Se2– ions in deionised water
solution. Elemental selenium (99.95%) was dissolved in an aqueous solution of sodium sulphite (pH
> 9) at 90o C to form a partial unstable Na2SeSO3 compound by reflux method. In order to obtain
the films lead acetate was mixed with trisodium citrate. To this solution, mixture of thiourea and
sodium selenosulphite was added. The grown film was washed several times with deionized water.
The synthesized film was annealed in air at 350o C for 15 minutes. Structural characterization of the
film was carried out with X–ray diffractometer system using CuKα radiation with wavelength
1.5418 Ao. The optical absorption study of the films was carried out using Hitachi U–2000
spectrophotometer. The electrical study of the films was carried out using four probe set up (model
no.DFP–02) scientific equipment, Roorke. 3. Result: 3.1 Structural analysis Fig 1. XRD pattern of
the sample Figure1 shows the diffractogram of the sample scanned in the range of 20–80o. The
XRD pattern reveals that Pb(S,Se) film is polycrystalline in nature. The planes

Advantages And Disadvantages Of Traditional Infrared Touch...
Traditional Infrared Touchscreens
Touchscreen interactive devices have become increasingly important in both consumer and
commercial applications. They're a large component of many everyday devices from your mobile to
your chromebook. They're "electronic visual displays that can detect the presence and location of a
touch within the display area (Bhalla, 2010)." There is considered four different groups of
touchscreen technologies each with its distinct advantages and disadvantages with some of the
variations containing sub groups within them: Capacitive, surface acoustic wave (SAW) and infrared
(Bhalla, 2010). The focus of this article will be on infrared touchscreens, specifically traditional
infrared touchscreens. Traditional ... Show more content on Helpwriting.net ...
The projecting mechanism of the IR touchscreen consist of Infrared LEDs, which lines two adjacent
side of the screen's bezel and the receiving component, that are commonly phototransistor, lines the
side opposite to the LEDs (Walker, 2012). Starting with the receiving component, the
phototransistor, it is a transistor that is sensitive to light. The basic concept that paved the path for
phototransistors was uncovered by Albert Einstein in his Nobel prize winning 1905 paper
(Handbook of Photoelectric Sensing, 1993). Einstein made the bold proposal that light traveled
through space in concentrated bundles (Known today as protons) (Handbook of Photoelectric
Sensing, 1993). Einstein also outlined how protons when striking materials liberate photoelectrons,
and the energy from the photoelectrons can be used to create a small current (Handbook of
Photoelectric Sensing, 1993). The property of a small current being produced by the striking of
photons exploited by transistors in order to create the photodetector, the phototransistor. In 1948, a
year after the transistor was invented, John Northup Shive created the first example of a
phototransistor where he used a beam of light instead of a wire as the emitter of a point contact
transistor, generating holes that flow to the collector (Electronic Circuits and Diagram–Electronics
Projects and Design, 2013). The first application of the

Universal Motors Aquires
SCMA 311
SPECIAL TOPICS IN SUPPLY CHAIN MANAGEMENT
SYNDICATE ASSIGNMENT
DUE DATE: 14th SEPTEMBER 2012
Assignment Brief
In your study syndicates, you are expected to read, analyse and interpret the key underlying issues of
the following case–study titled "The Universal Motor Company Acquires Semiconductors". Six (6)
questions have to be answered and these questions can be found at the end of the case study.
Your answers to the questions must relate to the issues in the case, however you are expected to
support your responses with appropriate and relevant literature from the prescribed text: Monczka et
al, 2009. You may also reference internet ... Show more content on Helpwriting.net ...
It seemed likely that this growth would be replicated by the entire auto industry. However, this
growth did not increase the market position of the auto industry, as the semiconductor industry was
growing faster than the automotive industry market component. Based on these observations, it
became clear that something had to change. The 1980 semiconductor supply situation was
intolerable. Of equal or greater concern, projected growth in electronics requirements appeared to be
unsupportable.
Forward Planning In 1980, the concept of forward planning, business planning, or strategic planning
was not commonly associated with the supply function. Supply management was most often thought
of as a reactive function organized to support manufacturing. Marketing, on the other hand, was
more often thought of as the proactive organization focused on the future of the firm. The failure of
management to recognize the strategic and futuristic implementation of supply management limited
innovative actions when dealing with a firm's supply world. The 1980 situation demanded new
thinking and a new approach to the acquisition of semiconductors. The supply managers involved
had little choice, given the circumstances. Supply had no experience with strategic planning. There
were no guidelines to follow. The responsible supply managers started with a clean piece of paper, a
mission, and a

Italse Model And The VASE Model
Manuscript #JSSP–17–3722:
Note: The original reviewer comments are stated in the bold text. The responses to the reviewers'
comments are stated in the blue Italic text. The modifications made in the revised manuscript are
highlighted Italic text and the original text is in the black italic font.
Editor's Comments:
Reviewer Comments:
Reviewer #1 Evaluations:
Overall Rating: Publish with revision required
Significance Level (4 = highest, 1 = lowest): 3
Reviewer #1 (Significance Level Comment):
The paper is well–written; however, some critical information is missing to make the study
meaningful and complete.
Reviewer #1 (Remarks):
The manuscript should include the following information to make the presented study meaningful
and ... Show more content on Helpwriting.net ...
More details of the analysis of the optical constant are reported previously [3]. Fig. 4 shows the
typical spectra obtained from VASE measurements at different ellipsometric angles and the fitted
data delivering the refractive index and thickness from VASE data (Ψ and Δ parameters). Fig. 4.c
shows an example of the refractive index and extinction coefficient. Hydrogenated SiCxNy thin
films are virtually transparent over the visible spectrum, which allows us to assume k (extinction
coefficient) is equal to zero over most part of the visible spectrum in the employed Cauchy model.
The low value of the best–fit mean–squared error (MSE) of about 4 validates the accuracy of the
modelling.
c
b a Fig. 4. (a) The phase parameter (Δ) and (b) shift parameters given by variable angle
spectroscopic ellipsometer and the corresponding fitted model are shown. An example of the

refractive index and extinction coefficient are illustrated in (c).
Section 3.3: Provide details of the equations used for optical band gap calculations. Include
information on how the direct or indirect nature of the optical transition was established.
The authors thank the reviewer for identifying this area of potential ambiguity. The following
highlighted text has been added to the revised manuscript.
Section 3.3 Optical Properties, Line 205: Experimentally, the band gap of amorphous
semiconductors is quantified using

Portable Laser Induced Breakdown Spectroscopy
Analysis of Minerals and Rocks by Using Portable Laser Induced Breakdown Spectroscopy
Naresh Kumar1* , Yuan Lu (渊卢)2, M.Al–Salai3,
1. Optics and Optoelectronics Laboratory, College of Information Science and Engineering, Ocean
University of China, Qingdao, 266100, China
Abstract:
Introduction:
Portable Laser Induced Breakdown Spectroscopy (Portable–LIBS) is a new technique for elemental
analysis and it is very fast, easy to use and also very light from other portable devices our portable
device is better for other devices, because we made this device for two things first to do LIBS
spectra and to capture the image of a sample after the plasma. Some of the commercial and portable
LIBS technique is presently convenient to use nowadays: ... Show more content on Helpwriting.net
...
The laser pulse was focused with a lens (L1) of 10.13 mm focal length on to the target. The plasma
light was collected with second lens (L2) of 29.08 mm focal length through spectrometer. In this
system we also collect the image of the sample after the plasma light by using lens (L3) of 38.1 mm
focal length through camera. The collected light is then guided onto a computer–controlled
spectrometer by a fiber optics. A computer was used for processing the data from the detection
system. The spectrometer is used in this system is AvaSpec–ULS2048 ULS symmetrical Czerny–
turner, 75 mm focal length it's bandwidth range from 200 nm to 1100nm, with an optical resolution
of 0.06–20 nm and their integration time 1.05ms to 10min. The software for obtaining and spectral
data processing generally it was to build for the LIBS system.
Sample:
P–LIBS were investigating successfully of ten mineral and rock samples from Pakistan and China,
Wollastonite (CaSiO3), Dolomite (Ca Mg (CO3)2), Calcite (CaCO3), Schist (SiO2, (Na, Ca)
Al2Si2O8), Quartzite (SiO2), Marble (CaCO3), Gypsum (CaSO4), Barite (BaSO4), Talc
(Mg3Si4O10 (OH) 2). All the Chinese samples are precisely investigated some kind

Sample Letter : A Program Director Who Is A Great Resource...
ACKNOWLEDGMENTS
I would like to express my deepest appreciation and thanks to both of my advisors Dr. Gamini
Sumanasekera, and Dr. Jacek Jasinski. I am grateful to Dr. Gamini for his great support and
guidance throughout my entire PhD program. In science, he is exceptionally knowledgeable and has
a great drive for developing homemade equipment and experimental setup as they become required
in a project. I am also thankful to Dr. Jasinski whose invaluable mentoring and encouragement were
vital to the completion of this dissertation. I have been inspired by his efforts in contributing to the
scientific community. I would like to acknowledge my Ph.D. committee members Dr. Chakram S.
Jayanthi, Dr. Ming Yu, and Dr. Jinjun Liu for their valuable ... Show more content on
Helpwriting.net ...
I was lucky to work with wonderful research associates and post–doctoral fellows during my
research. I wish to express a sincere thank you to Dr. Bijandra Kumar, Dr. Ramchandra K. Rao, Dr.
John Samuel Dilip Jangam, Dr. Dominika Ziolkowska, and Dr. Ruvini Dharmadasa. I am thankful to
my former and current labmates, George Anderson, Ruwantha Jayasinghe, Venkat Kalyan Vendra,
Swathi Sunkara, Ruchira Dharmasena, Rong Zhao, Sahar Pishgar, and Brandon Lavery.
My deepest gratitude and love to Farzaneh Hoveyda, my love, life partner, and soulmate who has
been a constant source of encouragement and support. She also helped me in writing this
dissertation through great discussion about various scientific aspects. I am heartily thankful to my
parents, Faramarz, Soroor, and my brother, Misagh, for tremendous emotional support.
ABSTRACT
SYNTHESIS AND FUNDAMENTAL PROPERTY STUDIES OF ENERGY MATERIAL UNDER
HIGH PRESSURE
Meysam Akhtar
April 19, 2017
Recently, high–pressure science and technology has flourished and rapidly advanced to impact a
wide domain of materials and physical sciences. One of the most substantial technological
developments is the integration of samples at ultrahigh pressure with a wide range of in–situ probing
techniques. Applications of extreme pressure have

Applications Of Photonic Circuits
2.1 Introduction
There have been extensive research in field the integrated photonics and industry in recent years.
There photonic circuits are advantageous as compared to conventional electronic circuits in a vast
range of applications.. Therefore, so much research have been done on photonic devices, such as
HCGs and photonic crystal based hollow waveguides, Bragg reflectors and their integrations with
electronic devices.
2.2 Literature Review
High index contrast gratings have been a very appealing choice over conventional DBRs in terms of
high reflection, size etc, also unlike DBRs, they provide phase and polarization control of light. The
huge mismatch between the electronic and photonic devices blocks the realization of high ... Show
more content on Helpwriting.net ...
So in order to increase the delay of the structure ,the input waveguide is extended with sharp bend
waveguide and the output waveguide with a smooth bend waveguide. The modified D–flip flop
structure has been operated with a delay of more than two fold of the basic structure by having
nearly the same CR at the output. The simulation results as well as compact design of the proposed
structure make it suitable to be a part of photonic integrated circuit.
Takeo Katayama et al. – 2016 [42] have done research on the optical coupling between a
polarization–independent high–index–contrast grating (HCG) and two orthogonal in–plane
waveguides. They have fabricated HCG with waveguides on a SOI (silicon–on–insulator) substrate.
The proposed waveguide–coupled HCG can be used into a polarization bi–stable vertical–cavity
surface–emitting laser (VCSEL), which would switch the output waveguide by changing the lasing
polarization of the VCSEL. It has been demonstrated that we can switch a waveguide with a strong
output by changing the polarization of light injected into the HCG. The light is more strongly
coupled to the waveguide in the direction perpendicular to the polarization of the incident light than
to that in the parallel direction.
Eungtaek Kim et al. – 2016 [43] have suggested functional passivation layers in the form of a
distributed Bragg reflector (DBR) which is composed of ZnS and LiF for transparent thin–film

Statement Of Purpose For A Robot
STATEMENT OF PURPOSE
"Motion Engaged", as it displayed, the robot turned around and moved towards the fourteen year
old, whose fathomless curiosity waited for answers to a thousand questions regarding the mysterious
object. Just one thought kept coming back to me – which one of them was a miracle, the
components that made the robot alive, or the man who knew exactly what to do with them. Both, I
finally concluded. If god has blessed us with semiconductors, it is man, who in his conquest for
progress has discovered in these materials the means of putting his dreams to shape.
My interest in VLSI is deep rooted. Even before I began studying it as a "Science" I remember
reading about the gadgets in magazines. From the invention of the first silicon transistor to the
microchip invented by Texas Instruments, from the first vacuum tubes and integrated circuits, to the
Intel microprocessor and the present day C.P.U. – every event has been a milestone which I have not
only read about but also savoured for how it has ... Show more content on Helpwriting.net ...
It was the time to water the seeds of VLSI that were sown earlier. In 2010, I completed my
schooling from Ahlcon International School, Delhi. This marked the culmination of a 12–year
period of brilliant schooling and I must admit that much of what I have gone on to do and achieve is
the result of those years. In August 2011, I enrolled for a 4–year Bachelor's Program at Jaypee
Institute of Information Technology, Noida and opted for Electronics and Communication as my
Major. I have spent the past few years in an atmosphere of proactive and vibrant academics. Amidst
students drawn from every corner of India and a faculty of highly qualified and widely travelled
mentors, I have flowered. I remember my teacher, Professor Satyendra Kumar, walk into the first
class of Basic Electronic Devices and Circuits and write on the board "The Next Big Thing Is Really
Small." And I knew I was in the right

Semiconductors: The Silicon Chip Essay
Semiconductors: The Silicon Chip
Silicon is the raw material most often used in integrated circuit (IC) fabrication. It is the second
most abundant substance on the earth. It is extracted from rocks and common beach sand and put
through an exhaustive purification process. In this form, silicon is the purist industrial substance that
man produces, with impurities comprising less than one part in a billion. That is the equivalent of
one tennis ball in a string of golf balls stretching from the earth to the moon.
Semiconductors are usually materials which have energy–band gaps smaller than 2eV. An important
property of semiconductors is the ability to change their resistivity over several orders of magnitude
by doping. Semiconductors ... Show more content on Helpwriting.net ...
They began studying the electrical properties of semiconductors which are non–metallic substances,
such as silicon, that are neither conductors of electricity, like metal, nor insulators like wood, but
whose electrical properties lie between these extremes. By 1947 the transistor was invented. The
Bell Labs research team sought a way of directly altering the electrical properties of semiconductor
material. They learned they could change and control these properties by "doping" the
semiconductor, or infusing it with selected elements, heated to a gaseous phase. When the
semiconductor was also heated, atoms from the gases would seep into it and modify its pure, crystal
structure by displacing some atoms. Because these dopant atoms had different amount of electrons
than the semiconductor atoms, they formed conductive paths. If the dopant atoms had more
electrons than the semiconductor atoms, the doped regions were called n–type to signify and excess
of negative charge. Less electrons, or an excess of positive charge, created p–type regions. By
allowing this dopant to take place in carefully delineated areas on the surface of the semiconductor,
p–type regions could be created within n–type regions, and vice–versa. The transistor was much
smaller than the vacuum tube, did not get very hot, and did not require a headed filament that would
eventually burn out.
Finally in 1958,

Chemistry Advances in Computers with the Work of...
Chemistry and technology has allowed so many advancements in today's society. It has allowed us
to have faster computers, better displays, bigger hard disks(hard drives),and it gives us the ability to
work, to create, and to play. The main focus point of my research is how chemistry has advanced
computers with the work of transistors. A transistor is a semiconductor device that can amplify,
control and generate electrical signals. Transistors look like integrated circuts. They are placed in
micro processors, known as the heart of a micro processor. As times go on transistors decrease in
size and increase in capability.
What was society like before the discovery of your technology? The discovery of transistors has
been around ever since ... Show more content on Helpwriting.net ...
How is your technolgyaffecting society today? In my opinion technology is having a negative affect
on society. You walk into resturants and you see a family everyone of their faces shoved into a
phone. But on the flip side it can be a positive affect. You see what all transistors do in all sorts of
technology. You have computers with games that look as if they are real life. Like if you were living
in the right part of the world you could look outside your window and see the same thing you are
seeing and hearing on the screen. You have an iPod that can fit in the palm of your hand yet it can
hold tens of thousands of songs. That is enough to play for a whole year! Technologly has come so
far with it's pros and cons of the world affect to all the advancements. You can have the world at
your fingertips, as long as you do not have a flip phone. But if you had an iPhone you could hold
music, apps, and much much more.
In your opinion, what impact will your technonly have on the future? In my opinion the future of
technolog wil have both a positive and negative affect, the same as what technology is doing now.
The technology of transistors will continue to have society in awe of what ever new product will
come out next. They will become friends with who ever gets the new product first. We will ask for
the things for christmas and boast about it too all of our friends. Because we have most storage for
all of our stuff. Transistors

Taking a Look at Quantum Dots
To begin with in layman's language or maybe for a person who has limited or little knowledge about
physics, quantum dots are materials that are small but are sufficient to exhibit quantum mechanical
properties. Quantum dots were first discovered in 1980. They exhibit electronic properties which are
between semiconductors and discrete molecules. That is the very reason for the unusually high
surface to volume ratio. The most visible use of quantum dots is in fluorescence where the
nanocrystal is capable of producing different distinctive colors determined by their particle size.
For the more experienced and the more technical personals, Quantum dots are semiconductor
nanostructures confining the motion of the conduction band electrons, the valence band holes or the
excitons and are in all the three spatial directions. The excitons are confined to the three spatial
directions only. There would be a doubt about what excitons is thus the definition; an exciton is a
state or rather a bound state of an electron or a hole which are attracted to each other by the
coulombs force. They are neutral quasiparticles that are generally existent in semiconductors and
also in insulators. They may also be found in some liquids.
The reasons for confinement can be electrostatic potential which can be due to external electrodes,
strain, impurities and doping. According to a lot of research that has been going on in this field, a
quantum dot has a discrete quantized energy spectrum.

The Chemical And Gas Sensors
Introduction:
There has been a rapid growth in the field of biosensing through both ultrasensitive chemical and
gas sensors. The bio–sensing protocols that are able to detect specific biological and chemical
species, sensitively and specifically (selectively) can noticeably influence our daily lives. The issues
related to monitoring of industrial emissions, medical diagnosis and public security are significant
application fields of gas sensing in particular. Nano–engineered materials including Carbon
Nanotubes and Graphene are being used to develop miniaturized sensors that can detect very low
concentrations of gases which are biomarkers of certain diseases like lung cancer in particular. The
composition of exhaled breath contains valuable information about certain volatile and semi–
volatile compounds which can be used to generate a chemical "fingerprint" and thereby screen
patients with lung cancer. Graphene and Carbon Nanotubes have been discussed for the
development of chemical sensing platform.
A. Graphene for biosensing:
Graphene is a 2–D form of carbon with planar structure and sp2 bonding. It is a single layer of
graphite with inter–planar spacings of 3.35 A0. It has attracted tremendous interest due to its
exceptional and unique properties. Some of its properties that are relevant to its widespread use in
gas sensors have been discussed below.
Properties:
1. The high specific surface area of graphene (both suspended and supported on substrate) provide
increased

Description Of The Hpge Gamma Ray Spectrometer
) Description of the HPGe gamma–ray spectrometer
A high resolution gamma detection system was used for gamma analysis. This system consist of an
ORTEC hyper pure germanium detector (HPGe), model number GEM– 15190, coaxial type detector
with a serial number 27–P–1876A recommended operating bias, negative 3 Kv. The detector used
has crystal diameter 49.3 mm, and crystal length 47.1 mm. The HPGe detector has a full width at
half maximum (FWHM) 0.9 keV at the 122 keV gamma transition of Co–57 and 1.9 keV at the
1332.5 keV of Co–60 gamma transition (Knoll, 2000). The detector has peak to Compton ratio
about 44 keV. Compton ratio is the number of net counts in the 1.33 MeV peak channels divided by
the average number of net counts in the channels representing the range from l.040 through 1.096
MeV which is part of the Compton region associated with the 1.33 MeV peak. Figure (2.5) show the
block diagram of gamma ray spectrometer.
The range of the multi channels analyzer (MCA) was adjusted to include the peak channel and the
range of interest in the Compton plateau (Madelung, 1991), (EML, 1990). High purity germanium
(HPGe) coaxial detector uses p–type material with lithium diffused outer contact. The inner contact
is ion implanted for the ultimate in reliability. Because of the small band gap (0.7eV) room
temperature operation of germanium detector of any type is impossible because of the large
thermally induced impossible because of the large thermally induced leakage current

A Study On Observation Of Photoluminiscene
A study on observation of photoluminiscene in Ruthenium–based dye (cis–diisothiocyanato–
bis(2,2'–bipyridil–4,4'–dicarboxylic acid)ruthenium (II))
Adlina Izny binti Ahmad
Advanced Material Laboratory
Faculty of Industrial Sciences & Technology, Universiti Malaysia Pahang
Kuantan, Malaysia
Abstract
Photoluminescence is light emission that form after the absorption of photons. Dye act as a light
absorber. Organic dye is one type of dye, have a small band gap and use as semiconducting material.
It will excite the excited electron after absorb light as energy from highest occupied molecular
orbital(HOMO) to lowest unoccupied molecular orbital(LUMO). The energy of photon must be
greater than energy of band gap in order to excite electron. ... Show more content on Helpwriting.net
...
Dye always acts as a light absorber. Dye will absorb light to excite the excited electron state from
HOMO to LUMO. So absorbed of photons will be happened and dye will fall back from LUMO to
HOMO. So emission of photon will be happened. So the wavelength during absorbance and
emission process can be identified by using Photoluminescene (PL) spectrometer. By knowing the
wavelength we can determine the concentration of dye. Ruthenium dye is one of the organic dye
where it contains small band gap, so it only needs small energy to excite the photon from LUMO to
HOMO. So if the dye absorb red colour it will reflect blue colour (refer figure 1). Figure 1: a wheel
of colour to estimate absorbed light based on colour of dye
Objectives
1. To speculate range of absorbed and reflected wavelength of light by Ruthenium–based dye based
on its colour
2. To characterize photoluminescence property of the dye using Photoluminescence(PL)
spectrometer; usng radiation source which energy is based on the speculated absorbed wavelength
3. To estimate energy loss via radiative recombination i.e., recombination of electron with hole in
the lowest unoccupied molecular orbital (LUMO) of dye.
Materials and instruments
PL spectrometer, gloves, 1000µL micropipette, deionized water, ethanol, 1 PL quarts cuvette, and
cis–diisothiocyanato–bis(2,2'–bipyridyl–4,4'–dicarboxylic acid)ruthenium(II) dye (Solaronix) Figure
2:

An Industry Analysis of Samsung Essay example
Question 1) How attractive is Samsung's primary (core) industry? Conduct an industry analysis.
Five Forces Model: 1. Barriers to Entry
Because of the extremely intricate and sophisticated nature of manufacturing semiconductors, a
competitor should expect high initial capital requirements to build facilities needed for production.
Cost to build a new semiconductor fab has gone up from $200 million in 1985 to $3 Billion in 2004.
Incumbent companies have capabilities to design newer generations of semiconductors with greater
amounts of memory and processing abilities that make older generations obsolete. Older generations
tend to drop half their amount in price one year after a new model is reduced (exhibit 6). The United
States ... Show more content on Helpwriting.net ...
The business level strategy of Samsung's memory chip business unit is an integrated strategy.
Remarkably, they have both a cost advantage and a value advantage over their competitors. In this
section we will describe how Samsung "widens the wedge" through cost and value drivers. The data
presented in Appendix 1 shows that Samsung's cost advantage accounts for majority of their
competitive advantage.
Value drivers: quality/reliability; large product mix including frontier products; customization; HR
Policies; and employees.
Cost drivers: economies of scale; learning and experience curve; product design; and single
production Site.
Learning and experience Curve: Between 1983 and 1985, Samsung allocated more than $100
million in into DRAM technology, even paying another firm to teach them how to produce 64k
DRAMs. As the market grew, firms tried to catch up to where Samsung already had a foothold. To
further make advancements efficiently, Samsung has had separate R&D groups compete within
their company to come up with the same solution.
Product Design: The chairman chose a stacking design that proved be advantageous over companies
that chose a trenching design. A core design was also used for their customized products.
Economies of scale: Samsung invested $1 billion dollars to create a production process that made a
12 inch wafer. A larger wafer meant more chips could be cut at the same time. See A2
Single production Site: It is estimated that this saved

When People Hear The Word Doping, They Think Of Athletes
When people hear the word doping, they think of athletes using drugs such as, erythropoietin, so
that they will have an advantage in their sport. However, the doping we are talking about today is
the type where elements are added to semiconductors to change its characteristics. Doping is the
process that changes the electrical conductivity of a semiconductor, like silicon. Doping is done by
adding foreign elements to the semiconductor so that the amount of valence electrons changes.
A semiconductor is a material that partly conducts electricity, it is in between an insulator and a
conductor. Semiconductors have four electrons in their valence shell, and since there needs to be
eight in the shell for it to be stable, it just has to connect ... Show more content on Helpwriting.net ...
Through doping, it creates two groups of semiconductors, N–type, which have a negative charge and
P–type, which have a positive charge. These different types of semiconductors are very important to
the world, because when the different types are used together they can create devices with special
electrical devices that have the ability to control electrical signals. Before semiconductors there were
vacuum tubes, which did the same job as semiconductors, but they were not as fast or as small as
them. Vacuum tubes, however, are very rugged and durable they can go through temporary overload
conditions.
Doped semiconductors are very useful, as they make up the base for diodes. A diode is an electronic
component that is used to make signal limiters, voltage regulators, switches, etc. Doped
semiconductors also make transistors, they are devices that regulate the current flow and they act as
a switch or gate for electronic signals. Transistors have three layers of semiconductors and when one
layer senses a small change of current it creates a rapid change in the current through the whole
component. As one can see, doped semiconductors are very important as they make the base of
many electronic devices that we use daily The effects of doping semiconductors were known for a
long time in devices like crystal radio detectors and selenium rectifiers. In 1885 and 1930, Shellford
Bidwell and Bernhard Gudden

How Was The X-Ray Diffraction Spectrum Of All Sulfurized...
3.1 Structural properties
Figure 1 showed the X–ray diffraction spectrum of all sulfurized Co–doped FeS2 films. The
comparison with JCPDS 01–071–1680 indicated a pure cubic FeS2 structure for all these samples.
The ratio between peaks from each sample demonstrated a poly–crystal structure. Also, no clear
preferential growth direction could be observed for each sample. The peaks of all Co–doped films
were very close to the pure iron pyrite peaks. No clear peak shift could be observed. This indicated
that shallow cobalt doping had little impact on the crystal structure of FeS2.
Scherrer equation, as shown in equation 1, was applied to estimate the average crystallite size of
these sulfurized films. . ... Show more content on Helpwriting.net ...
As more electrons were introduced, the net carrier concentration started to decrease until the
electrons became the majority carriers. This process may explain the change of conduction type and
carrier concentrations. The carrier mobility, however, decreased gradually from 6.52 cm2/V*s to
4.30 cm2/V*s as cobalt doping increased from 2 at% to 6 at%. This phenomenon could be explained
as the decreased mean free path of charged carriers because of the larger size of the incorporated
cobalt ions than the original iron ions. After switching to n–type, the increasing carrier concentration
may also contributed to the reducing of carrier mobility. As a consequence, cobalt doping served
well as an n–type dopant after 3 at% doping level.
3.2.2 Temperature Dependence
Figure 2 showed the relationship between the reciprocal of resistivity to the reciprocal of
temperature, graphed as a logarithmic plot. The resistance change of the Co–doped FeS2 samples
with Al electrodes were collected from room temperature (25oC) to 140oC. From Fig.2, the
resistance of all samples decreased while heating. This showed a general semiconductor behavior of
these Co–doped FeS2 films. The data in Fig.2 showed a linear dependence for each sample. The
fitting lines could be described by Arrhenius equation as shown in equation 2: . (2)
Here σ, k, T means conductivity, Boltzmann constant and temperature,

High Demand For Computer Chips
Computer chips are widely used today in computers, phones, tablets, and other electronics. The high
demand for computer chips requires a manufacturing process that is accurate as well as efficient. In
the past, chips have been manufactured out of many different materials including copper oxide and
germanium. Today, computer chips are manufactured using silicon due to its versatility as a
semiconductor and how readily available it is in the environment. This paper includes how silicon
became an important semiconductor, a brief history on the process of integrated chip manufacturing,
an analysis of the shrinking of manufacturing process, and newer methods of three dimensional
lithography. Silicon and germanium are used as semiconductors ... Show more content on
Helpwriting.net ...
Different combinations of n and p–type doping are used to create electronic components such as
transistors, capacitors, and diodes. Silicon became the top semiconductor in the 1960s due to the
oxide layer it forms, its ability to perform at higher temperatures, and its availability in nature. When
exposed to air, silicon forms a silicon dioxide layer on its surface that serves as an excellent
insulator allowing for small interference between different components. Compared to germanium,
silicon is able to perform at higher temperatures which becomes important when there are several
different components on a chip operating and generating heat. Silicon is also readily available in
nature, as it is a main component in sand whereas germanium is difficult to extract in large
quantities making it more expensive. Computer processors and graphics processors have become
increasingly advanced over the past 15 years, and require a process that is able to lay billions of
transistors in a short amount of time. This process starts out with a silicon wafer, which is made
from sand that it is melted down and extruded into a cylinder of perfect silicon lattices. This cylinder
is cut into several eighteen inch diameter disks that are close to one millimeter thick. The silicon
wafer is then annealed to remove the internal stresses of the lattice and then an

The Disposal Of Colored Organic Waste Water
The disposal of colored organic waste water from the textile industries causes serious problems to
the aquatic ecosystem and because of this the aquatic environment is contaminated which created a
serious threat to the living organisms. Textile industry is water–intensive resulting a large amount of
harmful dye effluent 33. The increasing awareness on environment issues the norms are being
specified by the governments of various countries 34. In view of complex chemical, molecular
structures and inherent toxicity of the dyes, the complete removal of dyes from the effluent became
difficult by conventional physico–chemical treatments like adsorption, coagulation and ion–
exchange. Moreover, these treatments only transfer contaminants from one phase to another and fail
to completely demineralize the toxic pollutants 35. The photocatalytic reaction has become a
desirable method to convert the organic pollutants into simpler and harmless compounds to
eliminate the environmental pollution 36. Therefore, it is highly desirable to develop a simple but
effective way to degrade these colored organic wastes. Conventionally, a biological treatment or
degradation process is utilized to decolorize the dyes, but it is ineffective for the complete removal
and degradation of dyes. In last few years, the catalytic process derived by solar energy or other
radiation energy has been studied for the successful degradation of harmful organic dyes into
environmental friendly materials. Recently,

Essay On Copper Oxide Nanomaterial
Studies on copper oxide nanomaterial have grown significantly in recent years due to its direct band
gap and intrinsic p–type behavior together with low cost fabrication and good opto–electronic
properties. Copper oxide shows two types of polymorphism namely, cuprous oxide (Cu2O) and
cupric oxide (CuO) [1]. Cupric oxide has absorbed light up to the near infrared region due to the
open 3d shell with a 1.2 eV in bulk, of charge–transfer type [2]. Recently, CuO has been paying
attention within the scientific community as a 'future material', because it has some unique magnetic
and super–hydrophobic properties which are not usually present in other metal oxide nanostructures,
such as TiO2, ZnO, WO3, and SnO2 [3]. Additionally, It confirms the ... Show more content on
Helpwriting.net ...
It has been reported in the literature that sol–gel method had influence of CuO nanoparticles [8–9].
Basically, sol–gel method is divided into two categories aqueous and non–aqueous sol–gel methods
both are beneficial for material preparation with simple laboratory equipment. Also, it gives various
morphologies at the synthesis stage (chemical transformation of the molecular precursor into the
final oxidic network) [10]. The aqueous sol–gel method has popular to fabricate bulk metal oxides;
they have a few limitations, when it works at their nanoscale counterparts. It becomes more complex
due to the highly reactive nature of water molecules with metal oxide precursors. In many cases, the
three reaction types (hydrolysis, condensation, or aggregation) occur simultaneously (and are
difficult to control individually), therefore slight variation in experimental conditions results in the
alteration of particle morphologies and is a serious concern regarding the reproducibility of a
synthesis [11]. Furthermore, the synthesized metal oxides are often amorphous, and it is difficult to
retain full control over the crystallization process. Apart from that the nonaqueous (or
nonhydrolytic) sol–gel method in organic solvents without involvement of water molecules is able
to defeat some of the major limitations of aqueous method. The advantages are closely related to the
diverse role of the organic

Conductive Polymers Are A Specific Section Under The Broad...
Conductive polymers are a specific section under the broad range of polymers, that have the ability
to effectively conduct electricity. They were discovered by accident in a lab by Hideki Shirakawa in
1974, yet their potential applications were not understood until early 2000s. They are made by
doping with n–type and p–type which forces electrons to move throughout the material which
normally would not happen because of a polymer molecular structure. They provide many
advantages over metals because of they are light weight, cheap, and functional versatile. Conductive
polymers are frequently used with rechargeable batteries, sensors, and light displays. Lastly, they
have a bright future with the world turning towards wanting more technology that is light weight
and integrated in the day–to–day functions.
A typical polymer is a very ductile, cheap, and light material that cannot handle high temperatures or
electrical conductivity. Polymers are generally used for plastic bags and bottles, crates, toys, and
insulation on electrical cables. Electrical conductivity is usually found only in metals because of its
small to nonsexist band gap between the filled and empty bands. Electrons are able to move freely
between the bands which is the current allowing everything to work. Polymers have a large enough
band gap that makes it very difficult for electrons to go between the bands. Large amounts of energy
would be needed to force electrons across this gap. However, with the addition

Advantages And Disadvantages Of Plastics
Introduction: First of all, the fundamental basis for much of modern life is the fact that electrical
charge flows through a material carried by electrons. For the most part, materials that effectively
conduct electricity–– conductors–– are ones that allow electrons to flow freely through them due to
their crystalline structure. Materials that restrict the movement of electrons are often classified as
insulators; however, the resistivity of substances is not black and white. Instead, it exists as a
spectrum between total blockage and no blockage, with many materials lying in between being an
insulator and being a conductor. Although the majority of electrons in these atoms stay in place,
some move through the material taking the ... Show more content on Helpwriting.net ...
Of course, many factors must be taken into account when choosing the material(s) when producing
resistors, including: voltage stress, thermal effects, lifetime, etc. Whether or not the resistor is being
used to decrease voltage, produce heat, and/or produce light dictates what you use to measure the
efficiency of the resistor. These measurements can range from resistivity(ohms) to temperature(F)
even to brightness(lumens) (Kostic, 2013). Due to the fact that in many circuits resistors are
primarily used for current limiters, this experiment will measure the resistivity of the resistor in
ohms. In order to accurately measure the resistance provided by the different substances we will be
using a device called a digital multimeter. A digital multimeter is a device used to calculate volt,
amps, and ohms. If the molecular length increases, then the resistivity of the resistor should increase
if resistivity is a function of molecular length. Due to the fact that resistivity affects current applied
to electronic devices, this experiment will utilize an L.E.D. after the resistor for qualitative data.
Throughout the history of electronics, many different materials have been used in resistors, mainly
varying

What´s Intellectual Propterty? Essay
Intellectual Property (IP) refers to the fabrication of human minds which perceive to be recognised
for exclusive rights. Pioneers, maestros and sole–proprietors are granted exclusive rights to a
collection of intangible assets for a specified period.
There are various types of IP laws. In Singapore, they are protected by trademarks, copyrights,
patent, geographical indications, registered designs, plant varieties protection, layout–design of
integrated circuits and miscellaneous amendments.
Even though intellectual property is an intangible asset to a company, they give business partners
and financial institutions the assurance to partner with and add capital with the chosen organisation,
making them as valuable as a tangible asset. ... Show more content on Helpwriting.net ...
Lastly, the invention must be useful and have some form of practical application. It should be
capable of being made or used in some form of industry.
However, if the invention of a method for the treatment of the human or animal body by surgery or
therapy, or of a diagnosis practised on the human or animal body, or an invention that could
propagates offensive, immoral or anti–social behaviour, even if it satisfies the key criteria for patents
it is still not a patentable invention. Trademark is a distinct symbol of sign that you can use to
separate your businesses or services from those of other businesses. This helps to protect businesses
by inhibiting other businesses from using its name or logo.
A design refers to the details of a shape, configuration, pattern or ornament carried out to an article
by any industrial procedure.
Registering a designs will primarily help you to protect your designs for industrial use. By
registering a design, you obtain a right to proprietorship and the right to prevent others from using
the design without your permission. You can make use of your design in many ways. You may use it
to save guard your market share by barring copying by others, license it to third parties for
commercial returns or sell the design for a sum of money.
To be eligible for registered design, it must satisfy two criteria in general. Firstly, the

The Atom And The Atomic Of The Energy Level Of Its Electrons
This energy will excite the affected atom, raising the energy level of its electrons. If these electrons
are excited past the range of the nuclei's binding attractive force, then the electron will jettison from
the atom. These two particles, the ionized atom and electron, are now detectable indicating the
presence of a neutron. This is the material ionization phenomenon (Crane and Baker). The nuclear
reaction induction phenomenon occurs when a larger nucleus is struck by a neutron. There is a
probability that the nucleus will absorb the neutron and become unstable. This instability results in
the decay of gamma rays or other particles such as alpha particles and protons. These particles are
easily detected and also indicate the presence ... Show more content on Helpwriting.net ...
In the conversion of alternating current to direct current, electrons from alternating current will also
enter the diode on the left. However, in part to the oscillating nature of alternating current, the diode
output of direct current will be relatively choppy, since electrons can only move towards the electron
holes in the P–type semiconductor (Kuphaldt).
As a result of the choppy nature of the direct current output, a capacitor is used to smooth the
electron fluxes (Copello). A capacitor is an electrical component that stores charge. In its most basic
form, a capacitor is made up of two metal plates with an insulated layer between them
("Capacitors"). As the electrons flow into the capacitor, their concentration and charge builds up on
one plate. Additionally, due to the repulsive nature of electrons, the buildup of electrons on one plate
will push the electrons from the other plate, creating a current out of the capacitor ("Capacitors").
This makes one plate positively charged and the other negatively charged. At this point, the
capacitor is storing energy. So, the capacitor smooths the fluctuating direct current by slowly
releasing its charge between input spikes ("Capacitors"). This generates a more consistent flow of
direct current to the electric grids.
Another primary component of the Farnsworth Fusor is its two concentric electrical grids. The DC
current produced by the diode will be run

Advantages And Disadvantages Of Zinc Oxide
Zinc oxide is a semiconductor material II–VI studied since the middle of 20the century. Most of the
physical properties of massive ZnO are therefore well known for several decades. The interest of the
researchers then declined, partly because of a major technological lock for the use of ZnO in
optoelectronics, namely the impossibility of doping the p–type ZnO.
The ability to grow thin layers and low dimensional hetero structures (quantum wells, nano–
columns, etc.) of good crystalline quality recently revitalized the research effort on ZnO, particularly
with the aim of obtaining effective devices for optoelectronics in the blue and near ultraviolet, in
complement gallium nitride. For this purpose, the main advantage of ZnO GaN is a lower cost,
enabled by the relative abundance of zinc over gallium. Zinc oxide powder is also used as an
additive in numerous products, for example plastics, ceramics, paints, pigments, cosmetics, etc.
In material science, another major benefit of zinc oxide is its strong exciton binding energy which
allows to preserve the exciton properties up to Room temperature. The cohesion energy of the
exciton is indeed twice greater in ZnO ... Show more content on Helpwriting.net ...
The first is the growth of quantum wells along non–polar axes. These axes, perpendicular to the axis
c, make it possible to overcome the internal electric field. The main axes used in growth are axes a
and m. The first samples quantum wells of ZnO / (Zn, Mg) O non–polar plan A were grown in 2007
on sapphire substrates [Cha07]. The other axis is to reduce the density of defects crystalline,
responsible for non–radiative losses. Most of the centers non–radiative are crystal dislocations,
which arise from mesh clash inherent to the heteroepitaxy method. Homoepitaxy, and therefore the
use of massive ZnO substrate, theoretically promises a clear improvement in quality crystalline. A
significant improvement was observed only very recently

Strengths And Weaknesses Of Singapore's National...
1. Explain the strengths and weaknesses of Singapore's national innovation system.
After gaining political independence from Malaysia in 1965, Singapore experienced a phase of rapid
industrialization based on export–oriented manufacturing by foreign MNCs. The approach was to
offer MNCs favourable conditions to locate in Singapore, with a view to increase overall skills and
technological capabilities. Singapore sought to build its science and technology resources through
the transfer of manufacturing technologies embedded in MNCs and foreign direct investments
(FDI). The local skill base was also developed through "learning by using" techniques among
workers and technicians employed by these foreign MNCs. Thus Singapore followed a dependent ...
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One important issue is the relative underdevelopment in local technological and marketing
capability. The success of a national innovation system depends on the effectiveness of two things:
(i) the deployment of new technologies and (ii) the development or creation of new technologies.
The dependent strategy has led Singapore to focus more on the deployment and diffusion of
technology by leveraging on large foreign high–tech MNCs, rather than fostering technological
development by local enterprises. The development of new technology in the MNC headquarters
and its transfer to their subsidiaries in Singapore has only been a major source of technological
upgrading in Singapore, rather than indigenous research and development. (Wong, 2000). According
to Low (2000), the innovative capacity and culture of Singapore had to be nourished, apart from the
efforts of the government in creating a conducive business environment
Developing the national innovation system using the dependent strategy can shift the government's
focus to creating more incentives for MNCs, rather than the domestic firms. Local small and
medium enterprises (SMEs) with some amount of entrepreneurial risk–taking capabilities become
overshadowed by MNCs and Government Linked companies (GLCs). This creates a credibility gap
when obtaining financial assistance schemes. Efforts must be made to ensure that these private local
SMEs are not dwarfed by the MNCs and

Essay on Physical properties
EGA108 / EG–279 ASSESSED SHEET 1
To be handed in via Blackboard by 5pm on Thurs Nov 8th. Show your workings in all cases – if you
want to include hand–written workings, embed these as a scanned or photographed image. e = 1.6 x
10–19 C NA = 6.03 x 1023 me = 9.11 x 10–31 kg kB = 1.38 x 10–23 JK–1
By: darky– 712402
1 List two aspects of materials behaviour that the Drude model can explain.
The Drude model can explain the Thermal Conductivity in metals and Electrical Conductivity of
metals.
List two aspects of materials behaviour that the Drude model can't explain but the Quantum Free
Electron model can.
Explains the effects of the temperature, impurities, and deformation on Electrical Conductivity in
which the Drude Model ... Show more content on Helpwriting.net ...
b) How the Quantum Free Electron Theory predicts that the conductivity of metals decreases as the
temperature increases.
In the Quantum Free Electron Theory the electrons are considered as waves, so the electrons will
have much similar behaviour to waves. The temperature is related to the heat capacitance. So each
element will have different heat capacitance.
The Quantum Free Electron predicts that scattering causes electrons to drop back down in Energy.
Which means that as the temperature goes down the stability of the electrons will increase; also the
amount of electron which can jump into a higher level will decrease thus more stability in the atom.
This means better conductivity in lower temperatures. So when the temperature increases, it will
cause vibrations that change the lattice, and the lower level electron will get excited to move into a
higher level which causes instability in the element. Thus, the conductivity will decrease.
c) How the Band Theory predicts that the conductivity of silicon increases as the temperature
increases.
The band theory gives explanations of how Semiconductors differ from metals because as the
temperature increases the conductivity increases. The Band Theory considers that for

Raman Spectra Of SP0. 7 Lab Report
Figure 6 shows the peak fitted curves Raman spectra of SP0.10, SP0.10A and SP0.10B in the range
200–800 cm–1 wavenumber. It is well known that the CuO is p–type semiconductor which typically
crystallizes into monoclinic structures and is defined by C26h (C2/c) space group. Three Raman
active (Ag + 2Bg) and six IR active (3Au + 3Bu) optical modes are predicted by group theory for
CuO. These normal lattice vibrations at the Γ point of the Brillouin zone are given on the basis of
group theory by the equation (Siddiqui et al 2016 c): Γ= 4Au+5Bu+Ag+2Bg. Based on the reported
zone–center optical phonon frequencies in CuO observed vibrational spectra were assigning to the
Raman active modes (Ag+2Bg) which peaks are located at 283.3cm–1, 329.8cm−1 ... Show more
content on Helpwriting.net ...
From the help of Kubelka–Munk (K–M) theory reflectance data was convert absorption mode [27].
As shown in figure 7 the as–prepared CuO nanostructures with different ratio of citric acid exhibit
different sensitivities to visible light, the absorption edge is shifted to shorter wavelength with
compact size and altered morphology. Our results point out not only the size but also the
morphology of the CuO nanocrystals affects the bandgap. It is quite observable from the figure 7b
that SP0.10A exhibits the hogher absorption properties in the visible region. Bhaumik, et al 2016
[28] reported the increase in absorption is highly desirable for better efficiency of a solar cell.
Therefore the SP0.10A sample exhibits the strongest absorbance and has a uniform flower–shaped
CuO crystal thus; we can say that the sample may be ideal solar absorbers. Figure 7: Kubelka–Munk
absorption spectra and Tauc's plot for the calculation of band gap of SP0.10, SP0.10A and SP0.10B.
Photoluminescence spectroscopy is an important tool to study the optical properties of a
semiconductor. Photoluminescence intensity may be directly correlated with the defect density in a
fluorescent material. However, the CuO has low emission efficiency (CuO is not a fluorescent
material) so there is a lack of luminescence data for copper oxide. Furthermore, recent theoretical
calculations indicate that although Cu vacancies are the most stable defects in CuO, they do not
introduce new states within the

The Synthesis Of Semiconductor Devices
The synthesis of semiconductor devices in microelectronics and photonics applications has always
fascinated me, and the field of developing electronic and photonic solid–state devices is a field that I
find continuously interesting and rewarding. The physics behind these devices and their
manufacturing are consistently setting new limits or allowing for new methods that produce useful
applications. By embracing and driving research, industries which rely on evolving electronic
devices and methods enjoy a rapid pace of development. Because of this, we see photonic solutions
proposed as an alternative to the more physical electronic devices. Moreover, we see approaches that
integrate these worlds. My interest in these fields will require an extensive academic and research
foundation regarding devices that rely heavily on quantum, electromagnetic and other phenomena. It
will also require me to initially focus my efforts before exploring a breadth of other fields and
applications that will become an integral part of my research repertoire. My academic interests and
career objectives span both theoretical and practice–based branches of learning. I have seen how
many factors in epitaxial growth of groups III and V semiconductor materials may render a great
theoretical design difficult to realize. The challenges in solving and computing for several equations
and in reaching a trade–off in designs also need to prove viability. This is only obtainable through a
deep understanding

A Presentation Of The National Nanotechnology Initiative (...
1. Introduction.
"There's plenty of room at the bottom"; this statement by Richard Feynman in 1959 during a
presentation to a meeting of the American Physical Society, is widely accepted as the spark that
initiated the present 'nano' age1. Nano, "dwarf" in Greek, is defined as one billionth, it follows that
the nanoscale is measured in nanometres, or 10–9 m. To put this in perspective; the average strand
of a human hair is roughly 75,000 nm in diameter, or from the other extreme 1 nm is the length of
10 hydrogen atoms lined up end to end.
Nanotechnology can be difficult to define, as its definition is often engineered to suit the researcher
and their field; this resulted in a need of a general working definition, which the national
nanotechnology initiative (NNI) established []. Nanotechnology is thus defined as possessing the
following features;
Nanotechnology involves research and technology development at the 1 nm to 100 nm range.
Nanotechnology builds on the capability to organize or manipulate at the atomic scale.
Nanotechnology creates and uses structures that have novel properties because of their small size.
.
2. Nanotechnology
Nanoscience involves a study of nanotechnology and nanomaterials, of which at least one of the
dimensions is in 1–100 nm range. Over the past two decades, nanomaterials have been a topic of
both scientific and technological interest2. Due to their compact dimension and enlarged surface
area, these materials possess new physical and

Electricity Is A Natural Phenomenon
Electricity is the directional flow of electrons between atoms. Electricity is a natural phenomenon
and is one of the most commonly utilized forms of energy. Electricity is used in order to do work,
such as generating heat and light. Electricity is measured in watts. Watts are the measurement of
power (current * voltage). Current is the flow of electrons measured in amperes (Amps). One
ampere is the amount of current when one coulomb (6.25 x 10^18 electrons) of charge moves past a
point over one second. Voltage is the force that causes electrons to move in a circuit. A volt is
defined as "the electrostatic difference between two points when one joule of energy is used to move
one coulomb of charge from one point to the other." (NDT Resource Center, 2013) A joule is the
measurement of energy that is used when one watt of power does work for one second (also known
as watt–seconds). When measuring electricity in large numbers, the standard unit of measurement is
kilowatt–hour. This determines the rate at which energy is being used, and how energy is quantified
in the United States. One kilowatt hour is equivalent to 3,412.14163 British Thermal Units (BTU's).
One BTU is the amount of energy required to heat one pound of water by 1°F (Princeton, 2013).
The current method of energy generation is from burning fossil fuels to generate electricity.
However, this method is inefficient because most of the energy invested in burning fossil fuels is
converted into heat instead of

Comparing The And Hetero Junctions
3.1 Homo– and Hetero–junctions
When the semiconductor materials are homogeneous throughout the entire structure is called a
semiconductor homojunction. Materials used to form a homojunction will have similar energy
bandgaps, On the other hand, when two different semiconductor materials are used to form a
junction, the junction is called a semiconducror heterojunction. The hetero junction is formed with
narrow bandgap material with wide bandgap material. Figure 1 shows three possible combinations.
When the forbidden band gap of wide bandgap material completely overlaps the bandgap of narrow
bandgap materials then it is called straddling which is applicable for most of the heterojunctions. In
staggered, a fraction of wide bandgap and narrow band gap are merged tog ether. In case of broken
gap there is a bandgap itself between energy bandgaps of different semiconductor. Fig.1. different
types of heterojunction (a) straddling (b)staggered (c) broken gap
Metal–semiconductor junction is an example of heterojunction. This junction can be created by
depositing a metal such as Al or Gold or Ag over a semiconductor (ptype/n type) wafer by different
deposition techniques (e–beam/thermal evaporation or sputtering/CVD). Depending on the work
function of the metal, this type of junction may behave as ohmic or schottky contacts. as the name
suggests if the contact is ohmic, the current –voltage relationship is linear as per Ohm's law. For
ohmic contact it is mandatory that the

The Most Important Qualities of Content in Research
There are three important qualities of content that researchers use as an assumption for most every
research. The first is the kind of atoms that the content is created up of. You have your fairly neutral
components and your substance components. Atom comes from the Ancient term atoms significance
inseparable. (Trefil, 2010) Atoms create up everything we can see, therefore content, and atoms
have very different qualities within themselves, as well as having different methods of being
organized or of connection together, all of which impact the actual and substance qualities of
whatever is created up of those atoms. Most components either perform electric current or don't
succeed to perform electric current. However, there is a third kind of content that is not a really
excellent electric conductor, and simultaneously, is not really an excellent insulator either. These
components are known as semiconductors, such as rubber and germanium (Trefil, p. 243). The fairly
neutral components have the same quantity of protons and electrons, which generally terminate each
other out making them fairly neutral. The substance factor offers with mixing more than one factor.
The second is the way those atoms are organized. An excellent example of this is by evaluating
atoms of fluid and atoms of shades. For example the atoms of fluids shift around freer than atoms of
shades which are loaded together. The third is the way the atoms are insured together. There are for
key qualities to

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