Semiconductor Definition and 400 Threads

Homework Statement Well basically, I need to design a model demonstrating the main characteristics of P and N type semiconductors by showing the creation of holes, movement of electrons in P type and the mobile electrons of the N type. I need a simple model design suggestion which I am able...

Calculate the conductivity of an intrinsic semiconductor at room temperature and from the following data: (n)Carrier density(where electron=holes)=2.9*10^19 carrier/m^3 Electron mobility = 0.45 m^2/V s Hole Mobility = 0.23 m^2/V s (q)Charge per electron/hole = 1.6*10^-19 coulomb/carrier...

Homework Statement Having some trouble with the following equation, I'm not sure what each term represents. The problem I have is does c,v have something to do with conduction and valence? But what is N and m? And what does it mean when terms are separated by a comma? Homework...

I did an experiment with Indium antimonide (InSb) in Liquid Nitrogen. I turned the sample one way in the B field and took a reading of the voltage (positive) and turned it 180 degrees and took a reading of voltage (positive, and a greater value). I use V_h = v1 - v2 / 2 and I get negative values...

Hello all ! I'm trying to solve a problem (link below) i have a problem to define the energy(s) distance {exp numerators} so i can't insert to the values needed into the equ. i wrote down. any help would be great ! http://rapidshare.com/files/406858775/ex3.pdf" TNX !

Hi Everyone! There are some things about semiconductors that have always puzzled me,and I think it's high time I got them cleared up! Here are my four questions...please help. 1. When an impurity atom (dopant) is added to an intrinsic semiconductor,(say germanium),is the band structure...

I'm interested in doing a Phd in semiconductor theory. Where would you recommend?

Homework Statement in Intrinsic GaAs,electron and hole mobility are 0.85 and 0.04 meter square/volt-sec and corresponding effective mass are 0.068m and 0.5m, where m=9.11*10^(-31)kg. band gap energy is 1.43 eV at 300K. ---calculate intrinsic carrier concentration(!) and Conductivity. Homework...

what really makes a semiconductor? Is it just the presence of a band gap but then insulators and metals also have band gaps or carrier concentration? Or we need to perform Hall measurements and also need to study I-V characteristics? Or do we need all of these parameters to establish a material...

doubt in semiconductor diode theory ? hello friends :smile:... in this picture diode is forward biased. positive terminal of battery repel holes n negative repel electrons , finaly electrons n holes recombine n eliminate each other. but its said that current flow is due to electrons ...

I'm wondering how one would go about measuring the conductivity of a semiconductor with variation in temperature, I assume the non ohmic behaviour prevents one from making simple voltage current measurements and then inferring resistance and the conductivity...any answers much appreciated...

Hi, I want to know what the important quantitative differences between the light produced by an atomic gas laser and that produced by a semiconductor laser are? I know that produced my atomic gas lasers are low power but high collimation, but semiconductor lasers seem to have higher power...

Hi, I want to know what the important quantitative differences between the light produced by an atomic gas laser and that produced by a semiconductor laser are? I know that produced my atomic gas lasers are low power but high collimation, but semiconductor lasers seem to have higher power...

Homework Statement Consider a model semiconductor with a bandgap of 1.0 eV which is doped with 10^17 /cm^3 acceptors for x<0 and 10^17 /cm^3 donors for x>0. E_c - mu = 0.1 eV on the far left and on the far right (far from x=0) Homework Equations The Attempt at a Solution...

Hi - just a quick question on notation. Take, for example, InxGa1-xAs . What is x? Thanks.

A question on semiconductors. I need to determine the carrier concentration and type. I have worked out the type but its the conc. that is getting me. I have the conc., n, as: n = wBJ / eV w is the width of sample, B the mag. field, e is charge, and V the Hall...

Homework Statement I am asked to show that the conduction electron density in an n type semiconductor is given by: n=\frac{1}{2} \left( -n_0 e^{-(E_c-E_d)/kT} + \sqrt{n_0^2 e^{-2(E_c-E_d)/kT}+4 n_0 N_d e^{-(E_c-E_d)/kT} } \right) where n_0=2(m^* kT/2 \pi \hbar^2 )^{3/2}For low temp p=0 and...

hi, I am reading my notes on semiconductor physics and this is a concept that is puzzling me - i always thought a vacancy and a hole were the same thing. in my notes it says that a hole has the same properties as a full band with one vacancy and so for consistency the hole must have...

Hello! There're very thin (4-15 nm) semiconductor films (passive film) formed on stainless steel by electrochemical method. In a electrochemical cell, I applied potential on stainless steel electrode to adjust Fermi level of the semiconductor passive film. I think that band bending take place...

P type semiconductor coil... The magnetic field orientation in a P type semiconductor wire, in which a DC current is flowing will be caused by the direction of movement of the electrons or the positive holes?

So, I am doing a little bit of research on how energy is created in solar cells. From what I understand, there is just a whole bunch of n and p junctions connected to each other electrons flow the same way. Or, electrons travel one way, and holes travel the other. So when you dope the silicon...

Suposse you have a material you are told is semiconductor, but don't know any more history about the material. What experiment(s) can be performed in order to find out if your material is direct or indirect?

Homework Statement Q1 A Si sample is doped with 10^16 per cm^-3 boron atoms and a certain number of shallow donors. The fermi level (Ef) is 0.36 eV above Ei (intrinsic energy level) at 300K. What is the donor concentration Nd? For Si at 300K ni(intrinsic carrier concentration) = 1.5 x...

I have a few questions about this effect. If I have some semiconductor of N type in which I have electrical field in x direction, and magnetic field in z direction \vec{E}=E\vec{e}_x \vec{B}=B\vec{e}_z Then Lorence force is in the -y direction because in N type of semiconductor n>>p so...

Homework Statement I'm attempting to understand better how optical transitions occur in a QW (more specifically quantum cascade lasers) with and without an electric field. If an electron in the second excited state falls to the first, is it simply the transistion matrix between these two...

Homework Statement Hello, everyone! As a rookie here, I want to ask a question for help. As for doped semiconductor, it is easy to find the answer based on the atom property. But for a intrinsic semicondutor, it seems hard to do so. I'd like to know what can be done to distinguish a n-type...

Hi guys, I just have a few questions regarding semiconductors and p-n junctions. How can I explain using an E vs k diagram why a silicon based device can be an efficient light detector but not an efficient light emitter? I imagine it has something to do with the fact that an electron in the...

Homework Statement I'm trying to find energy level above Ec where electron distribution makes a peak for a nondegenerate semiconductor. For this case we may take GaAs having Eg = 1.42eV at T = 300K. Homework Equations m_e=single isotrophic effective mass or m_0 energy states, g_{c}(E) =...

Homework Statement The resistance of a semiconductor decreases rapidly with increasing temperature. The main factor contributing to this effect is the rapid increase, with increasing temperature, of a. the speed of the random motion of the free charge carriers b. the concentration of the...

Hi, I have a super capacitor that is charged at 100,000+V at 0.1uF. Naturally it wants to give of its energy instantaneously in a spark; but I am trying to find a compound or semiconductor that can regulate the output of electricity from this capacitor without wasting the majority of the energy...

Hi Guys, I'm not sure that this is the right place to ask for it, and the thread may be moved to another section, but do anyone have the solution manual of : Semiconductor Devices Physics and Design not Physics and Technology I am despratley trying to solve a homework that questions...

Just to clarify - non equilibrium states in semiconductor means that the semiconductor is affected by external factors such as light?

Eg) Silicon Material When we say about mobility of a semiconductor - we basically have to consider its properties etc. One of it is impurities. Here we have to consider its TOTAL Dopant Concentration?

What is the difference between a solid state relay and a semiconductor contactor? Can both switch ac loads? This a link to a company that distinguishes between the two. http://library.abb.com/global/scot/scot209.nsf/veritydisplay/da7ec357f6a7461cc12573ad004e1e83/$File/2CDC110004C0205_07.pdf

I am curious about the operation principles of semiconductor lasers, but I never had the chance to go through the basic flow. I'd be grateful if someone posts a brief description of how the light amplification is achieved in simple terms.

I'm looking for a way to get accurate opinions, experiences and recommendations from others in industry on the quality of different electronic suppliers. Specifically, I want to know the quality of the suppliers of MCUs. What are your experiences with Freescale, Renasas, Microchip, Infineon...

hi folks, almost done my semester of physics. this problem has my goat, can't quite figure it out. Done web searches endlessly, but most of the links are pdf articles that I can't access. Homework Statement A donor electron moves in doped semiconductor, for which ε/ε0 = 17.9 and m* =...

hi I am doing my Electronics and Communication Engineering..I need a topic for paper presentation.Im more interested in semiconductor devices and device physics..It's like,i would like to address any physical limitation in the existing technology in reducing chip size.(this is the only topic i...

I read about the closing of GMT's semiconductor fab (that happened in 2001) because it was on the EPA's list of hazardous waste sites and that made me wonder, both historically and now what pollution has come from semiconductor fabrication?

Homework Statement I have a question on semiconductor device,, A drift current density of Jdrf=150 A/cm2 is required in a semiconductor device using n-type silicon with an applied electric field of E=25V/cm. Determine the imjpurit doping concentration that will achieve this specification...

Hi, Ok, so let's say we have a non-degenerate n-type semiconductor such that the Fermi-level/chemical potential is somewhere in the bandgap (probably needs to be low temperature). Typically in a metal you would say that the Fermi velocity is \hbar k_F/m_e. But since the Fermi-energy is below...

You are given a piece of metal of one square cm area and 10cm long. You do not know whether it is a conductor or a semiconductor. Devise some experimental setup to know the nature of the material.

I'm working on some calculations on Al0.35Ga0.65As & In0.65Al0.45As. Someone can tell me where i can find the elastic/piezoelectric/dielectric constants for these rare alloys?? A database for them exist for us to search?? Thx...

Couple of electricity questions here. 4. (a) Show that in a steady state, any isotropic material that obeys Ohm’s Law contains no regions with net charge. (b) In certain types of anisotropic materials, the conductivity  is not a scalar but instead a tensor that can be represented as a...

Hie. I would like to know anyone who knows or have idea on design static and dynamic model for Semiconductor Optical Amplifier? Currently my lecturer ask me to design using Optisystem software which I quit blur on designing this models. Anyone who knows and help me please. Thanks in advanced..

Hi, could you explain me polarization dependence of SOA amplifiers. and how to transfer the transverse electric (TE) mode to transverse magnetic (TM) mode. Are there any passive components to do it?

I am a graduate student working in semiconductor physics. I have been asked to give a presentation to high school girls about my field. The problem I am running into is that the organizers would like me to provide something hands-on that the girls can do relating to semiconductors. I have not...

Homework Statement This isn't a problem as such. This is about a practical I did, to verify the non-classical model of silicon conductivity (which increases with temperature) and then to calculate the band gap energy of silicon. Homework Equations This was the main equation of the model...

I'm wondering what determines Si indirect semiconductor? Si is cubic diamond structure. So it's optically and electrically isotropic (1st&2nd rank tensor properties). And why is GaAs direct semiconducto even though its crystal structer and chemical bonding is so simliar to Si? Isn't it crystal...

Homework Statement For a forward biased P plus N abrupt junction diode, Lp = 1 micrometer, and at x = xn (x' = 0), the ratio of the hole current to the electron current, Ip/In, is 100 in the steady state. Determine Ip/In at x' = 1 micrometer. Homework Equations Jn = In/A Jp = Ip/A...