Semiconductor Definition and 347 Threads

What is a purpose of a substrate in an electronic device? In particular semiconductor lasers, why is it made of semiconductor? Thank you.

http://physics.stackexchange.com/questions/156708/can-the-relative-permittivity-of-a-semiconductor-material-be-lower-than-1 To measure the relative permittivity of a p-type semiconductor material (a metal phthalocyanine ) , a M-S-M structure was made by thermal evaporation method. The...

Is there a way to fabricate semiconductors thigh common materials at home?

Given a material sample, what are the different experiments that one can perform on it to check if it's a conductor or a semiconductor. For eg, we can measure R at different temperatures. Anything else we can do?

How conductivity increases in n type semiconductor as ni^2 (formula nh multiplied by ne=ni^2 where nh=number of holes per unit volume and ne=number of free electrons per unit volume and ni=number of intrinsic charge carrier per unit volume remain constant?What is the use of increased number of...

Hi Guys, i need your help, where can i download free articles about the band gap of semiconductor materials (like copper (II) oxide). don't mention sciencedirect and arxiv, because i already explore that, and they provide limited research articles. thank you.

What exactly is conduction band?electrons from valence band jump into conduction band where they exactly go ,do they go to higher shell or subshell or orbital or stays in same place with more kinetic energy?

I'm very new to semiconductors. I want to do basic calculations. How would I go about calculating and graphing the energy of the electrons and holes given the magnetic field and the state. Also, how would I do the same for the electron and hole population.

I'm looking to buy a semiconductor cross reference book, for part numbers and diode and transistor parameters, including new smt parts. I had an old sgs Thomson book but it got lost in a move, if anyone could recommend me one that would be great. I don't want a link to a website cross...

I've been doing a bit of reading on bandgaps of semiconductors and alloys of semiconductors. I was curious to know is the bandgap of a material, say Silicon, determined or calculated experimentally? How do scientists usually determine this in the lab?

I have joined a research lab on semiconductor nano devices and have been recommended to study the Robert F. Pierret book "Fundamentals of Semiconductor Devices" but unfortunately I could not understand most of the concepts after reading first three chapters. I am a computer science graduate with...

If you research the materials semiconductors are made of you will find things such as aluminum gallium arsenide. How do you determine what the p-type and n-type are made of? Shouldn't there be a structural difference in order to create band gap?

I am getting an opportunity to do PhD in semiconductor devices. The professor is quite active in the field and publishing good research. I have no background in solid state physics. How difficult it could be with a computer science background? Also where should I start once enrolled in a...

Hi Guys, I read that the Fermi level of semiconductor, like germanium, is in-between the completely occupied upper band and conduction band, i.e. right in the gap. Why is that? shouldn't it have beed exactly the highest occupied level ?

Hi all, I have a question and ask for a discussion. Can the pumping current of the semiconductor lasers such as DFB laser and FP-LD, be smaller than zero? Best Regards, Jason.galq

A new type of energy storage described which uses quantum way to store energy. ''Battenice''. http://techon.nikkeibp.co.jp/english/NEWS_EN/20140224/335902/ How exactly new energy levels could form under UV light? What do the mean?

please see attached image for problem if a dopant gives an electron it's an n-type, if a dopant takes an electron it's a p-type. i can't see how to relate the hall coefficient value to the property of being a n-type or p-type semiconductor? any pointers on this would really be...

I'm trying to understand the form of the absorption spectrum of a T=0K intrinsic semiconductor. The valence band/conduction band energy diagram looks like; http://postimg.org/image/wyzvo9lsr/ As E = \frac{\hbar^2 k^2}{2m^*} where m^* denotes the effective mass. The image doesn't...

Homework Statement Estimate the electrical conductivity, at 135°C, of silicon that has been doped with 3 x 1024 per meter cubed of aluminum atoms. Assume values for electron and hole mobilities of 0.03 and 0.007 m2/V-s, respectively. Homework Equations σ=|e|(ne*μe+nh*μh)...

My question is about drift and diffusion current.In a semiconductor diode no "bias" condition diffusion is present and due to transfer of charges due to diffusion depletion region created and then this region has ions which produce electric field which results in drift current due to force the...

Homework Statement The current-voltage characteristic curve of a semiconductor diode as a function of temperature T is given by the equation: ##I = I_0(e^{|e|\Delta V / k_BT}-1)## where e is the base of the natural logarithm. |e| is the charge of an electron k_B is the boltzmann's...

I don't know if I am asking some stupid questions but I can't really move without knowing them. (1) In reverse bias situation electrons attracted towards positive terminal and hole attracted towards negative terminal widen the depletion region .My question is that why can't these hole...

Homework Statement Here is the problem in the book: Here is the solution: What I don't get is why the solution defines the fraction to be ni/(5*1022). Shouldn't it be 2*ni/(5*1022) since we have both donors and acceptors, so there are actually twice the number of atoms. Also...

I'm aware that you "dope" them with phosphorous for n-type and boron for p-type (I'm aware other materials can be used and other dopants are preferred in other situations). My question is exactly how is this done? Temperature, Pressure, Sputtering, etc.A white paper or something of the exact...

Hi, I am looking for a good book or any other online resource on semiconductor physics. What I need the book to cover is: The PN junction i.e. the diode BJT transistors MOSFETS In particullar I am interested in the derivation of the equations of the above components, the Shockley...

hey guys i just wanted to confirm something; so, for systems of continuous energy states (or small separations of discrete energy states), we can plot a graph like this and call the fermi energy the middle point where Probability=1/2. like this where, if T=0K, the transition from...

I understood that the fermi level is a hypothetical energy level given by the Fermi-Dirac distribution where the probability of finding an electron is exactly 50%. My question is: it always takes (Ec-Ev) energy to excite the electrons in the conduction band in an intrinsic semiconductor or...

Attached is a picture of three different electron configurations in a semiconductor. It seems from the author of my book that it should be obvious that the middle one has a lot lower conductivity than the 2 other. Why is that? I mean it is possible for the electrons to move in the conduction...

In my college, we used this transistor named SL100 and another one named CL100 for various experiments. But why are they named that way? I browsed the net for an answer for almost an hour but couldn't find a proper answer to this? What does S and L mean? what does 100 mean? From the Datasheets...

Homework Statement The lab is attached. I've also attached the pre-lab just for the diagram. Homework Equations The Attempt at a Solution Can anyone think of some good errors for this lab? We ended up with ~80% error. I've thought of two: 1. Adjusting the potentiometer so...

How do the effects of semiconductor semiconductor doping affect the Hall effect? For instance, consider number 4 and 5 in the following sample: Using the right hand rule, B points downwards, conventional current points to the right (because of the 5V battery), and therefore, the force...

Hi, Iam having a hard time understanding the benefits of using a semiconductor to construct e.g. a photodiode that creates a current in proportion of the energy deposited by radiation. Text books says that semiconductor is preferred as detectors due to high density (larger chance for...

Hi, Iam reading the book Glen F. Knoll Radiation Detection and Measurements, and Iam having a trouble understanding a certain part of the chapter about semiconductor, he writes: Electron-hole pairs that are created within the depletion region by the passage of radiation will be swept out...

Main reason why semiconductor is used and not a "pure" metal for detec Hi, I have question regarding why semiconductor is preferred in the field of radiation detection. I have read that they can be doped and their conductivity can be manipulated, but I can't see why this is not possible...

Homework Statement Explain why a pure semiconductor crystal will always have equal numbers of electrons and holes present as electrical carriers. Explain why a crystal with additional donor impurities will norally have more electrons in the conduction band than holes in the valence band, still...

Homework Statement P-type silicon can be doped in the range from 5x1014 cm-3 to 1020 cm-3. Determine the maximum possible number of minority electrons in a neutral P-type region if the device area is limited to AD = 1 cm x 1 cm and the thickness of the P-type region is limited to tP=100 μm...

I do not know if this question relates to this division and would appreciate if it would be moved to proper division. I want to buy a piece of fine, pure, highly doped semiconductor with dimensions approximately: 7 cm X 7 cm X 1 cm (2 in. X 2 in. X 1/2 in.) It supposed to be just fine and...

Hi, I was wondering if someone could tell me what the best way would be to determine if a semiconductor laser is broken using a multimeter? I have a semiconductgor laser that is still emitting but the signal appears lower than expected and it is hard to tell if it is broken internally...

What exactly is a concentration of acceptor in p-type semiconductor? The symbol is Na. Lets say there's a Silicone, and it has 3 valence electrons, when it receives electrons (releases hole), it becomes negatively ionized, right? So that should mean Silicone is an acceptor, right? But what is...

Homework Statement "Use the equation I=nAve to justify why charges travel faster in semiconductor than in metallic conductor. Assume that the dimensions and current are the same. " Homework Equations I=nAve I know I = current, n = number density, A= cross sectional area v= drift...

This is a question about the band gap. In a semiconductor, the chemical potential is in between the valence and conduction bands, so that the valence band is full and the conduction band is empty at T＝0. What happens if you try to add another electron to the system? It seems that it wouldn't...

In p-type semiconductor the charge carriers are said to be positive, that is electron hole. But still isn't the electrons are movoing ? If positives move to the right that means that in reality electrons are moving to the left. Then how is it that the hall effect experiment for p-type...

For intrinsic semiconductor, the know its conductivity=2 neμ , where his the number of electron per cubic meter, e is the charge of an electron, μ is the electron mobility. But if I want to calculate the conductivity of a conductor= neμ. Why not consider the hole in? Electron leaves its...

Hi, I am planning to join M.S in MIS/IS next year. For e.g:-i)http://mays.tamu.edu/info/prospective/undergraduate/mis/ ii)http://business.uc.edu/programs/graduate/ms-is/academics.html Is it possible to pursue a phd in Semiconductor Devices/VLSI/Device Physics after this? Or, an MS in...

Homework Statement If a sample of pure silicon at 300 Kelvin has a resistivity of 950Ωm, and if the electron-to-hole mobility ration is 3:1, with the electron mobility equal to 0.12m2V-1s-1, what are the intrinsic hole and electron concentrations? Homework Equations I know resistivity...

Greetings everyone, I need information about how semiconductor interacts with electromagnetic radiation, the absorption, scattering, transmission and reflection properties of semiconductors. I also need to associate this information with free charges or bound charges. I would be grateful for...

what is it ? please explaining the physical operation of semiconductor diode (pn junction).

If I have a semiconductor junction of p-i and an electric field applied to it in forward bias, will the current flow?. How is the depletion region formed in intrinsic region since there are no free carriers there.What will be the electric field distribution through the intrinsic region?

Hello! I am trying to carry out wavelength depended photoconductivity experiment to a semiconductor thin film material. I use keithley 2400 sourcemeter. I do apply voltage to the sample under pressure and read the current. My problem is when i apply a constant voltage to the sample i see that...

Homework Statement The resistivity at room temperature of intrinsic silicon is 2.3*103 Ωm and that of an "n" type extrinsic silicon sample is 8.33*10-2Ωm . A bar of this extrinsic silicon with 50*1000 mm has a steady current of 100μA across it. The voltage across the bar is found to be 50...