Name: Jai Kant
UFID- 76691873
Date of Experiment: Mar 13th, 2014
Pre Lab Report Sixth week- Photolithography
Problem 1: What is thermionic emission??
Answer: The term thermiionic emission comes from the phenomena of quantumm mechanical tunneling which takes place in some special circumstances. It sometimes happens that electrons with energy less than the barrier height to cross the barrier passing through it instead of over is called tunnneling effect. In semi conductors we can see this in heavily doped material where the current in the forward direction arises due to tunneling of the charged particles with energies close to the Fermi level but not the actual barrier height. This kind of emission due to tunneling is called field emission. Now if we increase the forward bias voltage, the electrons acquire enough energy to tunnel through the thin depletion region. To avoid this kind of tunneling and get a pure current flow we raise the temperature to a certain point such that the electrons get enough energy to cross the barrier and no longer tunnel through it. This temperature generated effect is called pure thermionic emission.
The above figure is a representation of the thermionic emission, where V – applied forward bias, EF is the Fermi level.
Problem 2: What is Schottky Barrier height??
Answer: It is the difference between interfacial conduction band edge (Ec) and the Fermi level (Ef). From the figure below we get a better idea of the barrier height which is given by ΦB(PhiB).
Now the value of the Schottky barrier height is dependent on the contact resistances of the metal and semiconductor under consideration. The idea of a schottky contact is that when metal and semiconductor are brought into contact with eac...
... middle of paper ...
...stead of one gap?
Answer: The advantages of using several gap to measure the transfer or contact resistance using the TLM (transmission line method) are as follows:
1) A cylindrical TLM has been recently developed and it simplifies the fabrication process.
2) It gives a more symmetrical current flow pattern.
3) Using more gaps helps eliminate the edge effects and get a uniform distribution.
Reference:
1) https://elearning2.courses.ufl.edu/access/content/group/UFL-EEE5354L-40146-12014/Week%209%20-%20Presentation%20-%20Photolithographic%20Exposure%20Systems.pdf
2) www.wikipedia.org
3) https://elearning2.courses.ufl.edu/access/content/group/UFL-EEE5354L-40146-12014/Week%209%20-%20Presentation%20-%20Photolithography%20Basics.pdf
4) http://etidweb.tamu.edu/ftp/ENTC250/Lorenzo/Semiconductor%20Po
5) http://www.ece.gatech.edu/research/labs/vc/theory/photolith.html
Practiced by thousands who shared no common tradition or training from the earliest days of taking photos, the first photographers were disciplined and united by no academy or guild, who considered their medium variously as a trade, a science, an art, or an entertainment, and who often were unaware of each other’s work. Exactly as it sounds photography means photo-graphing. The word photography comes from two Greek words, photo, or “light”, and graphos, or drawing and from the start of photography; the history of the aforementioned has been debated. The idea of taking pictures started some thirty-one thousand years ago when strikingly sophisticated images of bears, rhinoceroses, bison, horses and many other types of creators were painted on the walls of caves found in southern France. Former director of photography at New Yorks museum of modern art says that “The progress of photography has been more like the history of farming, with a continual stream of small discoveries leading to bigger ones, and in turn triggering more experiments, inventions, and applications while the daily work goes along uninterrupted.” ˡ
Thin = less than about one micron (10,000 Angstroms - 1000 nm) Film = layer of material on a substrate.
However, it can also be located in the in the bulk of the silicon both
Thus, wavelength of photoelectric threshold of the metal should be longer than 400 nm. However the metals used, zinc and copper, have photoelectric thresholds of 290 nm and 270 nm respectively. Thus the photoelectric effect did not occur during the experiment.
An outer shell electron will then replace the captured inner electron, emitting characteristic X-Rays in the process. If the daughter nucleus is in an excited state, gamma rays will be also emitted according to equation (4). X-Ray fluorescence arises when a sufficiently energetic electron knocks an orbital electron out of an inner shell, followed by subsequent electron capture and X-Ray emission. Bremsstrahlung radiation is produced by the scattering of electrons due to a strong electric field surrounding high Z nuclei.
-Ionization Energy: the amount of energy required to remove an electron from a neutral atom
Plots for transmission coefficient and reflection coefficient of simulate results are shown in figure 3.4(b)
Each of the children did very well with identifying concepts of a book the first child that we will look at is 6 years old. She goes to kindergarten all day and has grown up with many books around. She was able to hold the book right side up for me, show me the front cover, and show me the back cover. She was also able to show me the title page of the book. Lastly she was able to show me the first page of the text. Although she did do a good job of pointing out some main parts of the book she did struggle with a couple others. She wasn’t able to turn some of the pages of the books she would skip three or four at a time. She also had a hard time pointing to the title of the book if it was not in the top of the cover. Lastly the child could not tell me what an author and illustrator did. The next section was conventions of print the child was able to do everything on this list with excellence. She was able to show me where the text was, show me where we start to read at, read left to right, top to bottom and knew that when you reached the end of a line you would have to go to the left...
E is the energy difference between the highest occupied and lowest unoccupied molecular orbital (HOMO and LUMO).
The voltage signal produced by the thermocouple can be converted to electrical signal in many ways. One way to do this is by using a power serials polynomial. The coefficients in the power series are known for each thermocouple type and using the thermocouple output voltage, temperature can be calculated. 6
Imaging Technology Scanners are used widely in the United States to filter millions of people through airport security checks, in response to terrorist threats. The systems that have generated the most controversy are the passenger full-body scanners. Two main types of full-body scanners used in airports are Backscatter and Millimeter-wave technology units (Accardo, 2014). Although they radiate different type of radiations, both scanners serve the same purpose to detect contraband concealed under clothing without the need for a strip search. Although Imaging Technology Scanners are deployed to further public safety efforts, they have also generated widespread public concerns. These concerns address public health, privacy and equity issues.
Digital-less photography is an old way to take pictures that is not much used anymore. There are many different ways to produce the actual image when it is digital. In this paper I want to describe how dark rooms work, different thing that can happen to the picture during the process, the change in from digital-less to digital photography, this history of photography, and things you need for a darkroom.
[5] M. Uchida, Y. Fukuoka, Y. Sugawara, N. Eda, A. Ohta, J. Electrochem. Soc. 143 (1996) 2245−2252.
The idea was to improve 3d printer with special technology, a single printer, with multi material features, can transform from any 1D strand into 3d shape, 2d surface into 3d shape or morph from one 3d shape into another. The shape of 3d technology is basic mode for 4d. Objet Connex multi-material technology is an 3D printing important part of his work – and is being used extensively in this new process. The Connex multi material technology allows the researchers to program different material properties into each of the various particles of the designed geometry and harnesses the different water-absorbing properties of the materials to active the self-assembly process. With water as its activation energy, this technique promises new possibilities for embedding programmability and simple decision making into non-electronic based materials.
Additive manufacturing technology, more commonly known as 3D printing, is changing the world as we know it. Within the last few years, the 3D printing revolution has pioneered a new way of hyper-local manufacturing, allowing for the production of new things that were previously impossible to make. The rapidly evolving technology is making people wonder, “What will be next?” Avi Reichental, the President and CEO of 3D Systems, is the man with the answer. As the owner of the world’s first and largest 3D printing company, Reichental is on the forefront of 3D printing. In the TED Talk “What’s next in 3D printing,” Reichental advocates 3D printing technology as a way to propel society into the future while also connecting people to their heritage.