Semiconductor physics is the branch of solid state physics that focuses on specific properties of semiconductors. It studies dynamics of different perturbations (mainly electrons and holes) in the semiconductor crystal and the ways to affect it.

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Why is nitrogen not used as a pentavalent impurity?

I don't understand why nitrogen though a fifth group element is not used as a pentavalent impurity in doping a semiconductor.
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Can electrons move back into the donor level

In a n-type semiconductor electrons from the donor level move up into the conduction band but can they move back down? Also in a p-type semiconductor electrons move to the acceptor level from the ...
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N-type semiconductors and the number of holes?

Let us say we have Germanium which has been doped with antimony. Antinomy has a a fifth valence electron not involved in bonding. Is this electron in the valence band? I ask because all texts on the ...
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How do we predict electrical properties of a material using scattering data and vice-versa?

I know that the band gap is related to conductivity. What I'm wondering is what it is like for an experimentalist who is trying to figure out what an unknown material, a black box, is doing. The only ...
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Does the Shockley Diode Equation hold in a dynamic circuit?

Consider the following simple photodiode circuit: I've created a real-life version of this circuit, and I've detected that $I$ is oscillating: $$I(t)=I(t+\tau)\tag{$\tau\approx ...
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Please explain The Bias-Dependence Change of Barrier Height of Schottky Diodes under applied Bias

I would like to know how and why does the barrier height of Schottky Diode change under the applied forward and reverse bias conditions.
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Silicon/silicon dioxide interface

Suppose we have an interface of silicon/silicondioxide. If we shine light on the top surface electron-hole pairs are generated in silicon. since there is always a field directing from surface to bulk ...
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What is the temperature evolution of the conductance of a quantum chaotic system?

I read this really nice article by Abanin and Levitov: http://arxiv.org/pdf/0704.3608.pdf They argued that the mixing of the quantum edge channel at the vicinity of a PN junction is described by the ...
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Why is the diffusion capacitance greater than the depletion capacitance in a p-n junction?

In a p-n junction the total capacitance is the sum of depletion capacitance and diffusion capacitance and it is mentioned that the diffusion capacitance is almost a million times greater than the ...
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32 views

why some elements of same group cannot be used for doping semiconductors?

15th group elements like As, Sb, P can be used for doping whereas N and Bi cannot be used for doping even though they too belong belong to 15th group. Why ?
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Optical absorption in a semiconductor for $E<E_g$ [duplicate]

Quoting from Solid State Electronic Devices (by Ben G. Streetman and Sanjay Banerjee): A photon with energy less than $E_g$ is unable to excite an electron from the valence band to the ...
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41 views

Effective masses for different direction

Assume we have an indirect semiconductor where the effective mass becomes anisotropic in different directions. Usually, one talks about a mass in parallel and perpendicular direction referring to ...
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How to check the ohmic contact to the film?

I have a thin semiconductor film deposited on an isolating substrate. I would like to check different metals to find out do they form the ohmic contact or Schottky barrier. What is the best way to do ...
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How can we determine the inbuilt barrierpotential and electric feld for a given band diagram?

Suppose I have got two p type silicon materials of different concentrations (the difference in thier concentrations is small but considerable enough that their fermi levels differ by noticeable ...
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62 views

Why can't we dope the intrinsic semiconductors with sixth or second group elements?

Suppose we want to make an n-type silicon semiconductor why do we use arsenic or phosporous as an impurity? Why cant we use selinium or terellium? Infact my doubt is when we use sixth group element ...
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1answer
37 views

What factors cause the velocity saturation to occur at different electric fields for different materials?

In semiconductors the velocity of carriers gets saturated after a certain value of electric field. In silicon it occurs at around $10^4 kV/cm$ and in GaAs at some other value. What factors are ...
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How to obtain ballistic transport in a device?

I would like to know the ballistic device characteristics and illustrations (if any) to understand how can we overcome the dependence of current on carrier mobility .
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53 views

How should semiconductors be understood? [duplicate]

In the chemistry setting, a doped semiconductor is a crystal lattice with holes/extra electrons in it. In the band/quantum mechanical picture, these holes/extra electrons can be seen as the amount ...
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44 views

Diffusion and Drift currents in a PN junction

In a forward-biased PN junction, the potential barrier decreases, allowing more majority carriers from one side to diffuse to the other side where they are minority carriers. After they cross the ...
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2answers
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Can the current in a semiconductor be independent of mobility of charge carriers?

Can any device be made in such a way that the current through it is independent of carrier mobility? In a usual semiconductor or a device which is made of semiconductor material the current due to ...
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What is the performance of a silicon crystal that makes it an essential component to computing

I'm on a thread of interest in the precise physics that allow the creation of the computing process. It began as a question posted in search of an understandable explanation of what physical form ...
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27 views

P-N junction voltage under polarization

All the books that deal with the p-n junction under applied bias asume that the same equations used for the equilibrium case (no bias) can be used for the biased case provided that the juntcion ...
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1answer
40 views

Schottky Barrier - Why energy band levels at interface are assumed to remain the same that bulk

I have been chewing up some time ago the Schottky-Mott theory of Schottky Barrier height (which ignores the surface states). All the deduction seems to ground on fundamental thermodynamical principles ...
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37 views

How does a minority carrier diffuse?

I have gone through a lot of questions but none of them ask how do the minority carriers approach the depletion layer in the first place. When a p-n junction is formed, negative space charge ...
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29 views

Polarization selection rules

So, I am just reviewing some of my physics stuff, and I have read something about polarization selection rules in inter-band-transitions in quantum wells. If I calculate them, I get a strength of 1/2 ...
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1answer
80 views

Sold-State Band Structure - connection between Fermi Energy, Fermi Level and Work Fuction

I've been struggling with the concepts of these three terms - Fermi Energy, Fermi Level and work fuction. Now, I was given these definitions (in the context of semi-conductors): Fermi Level is the ...
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Why is effective mass of holes positive?

i am trying to understand this. I know that the effective mass of electrons or holes is calculated as: $$m^* = \frac{h^2}{(4\pi^2)\frac{d^2E}{dk^2}}$$ Now,if i look at this plot for example: I ...
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26 views

Alignment of Fermi Levels between Metal and Insulator

If I stick a metal and insulator together, will the Fermi level of the metal align with the insulator? When people draw a band diagram for a metal-oxide-semiconductor heterostructure, I never see ...
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in an organic semiconductor, what is the average distance travelled by an exciton?

In an organic semiconductor, what is the average distance travelled by an exciton up to recombination? How is this value related to the morfology / structure of the organic semiconductor?
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Extrinsic Photoconductor Charge Carriers

I'm studying some materials on semiconductors, and a section on photoconductivity has left me somewhat confused. In an extrinsic material, is photoconductivity the result of electrons moving from the ...
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23 views

How does Passivation in Mercury-arc-valve cause “diode” behavior

Does passivation of lead anodes cause them to become semiconductors? Or even become diodes (eg. a p-n passage)? How does this work on an atomar level? This question has been risen by trying to ...
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1answer
34 views

Hall Effect p-type Germanium holes density

I had to do some experiments with a Hall Effect Apparatus of Leybolds with a p-doped Germanium plate, this is the datasheet (pdf). eq. (1) $U_H=R_H \frac{IB}{d}$ $U_H$ = Hall voltage $R_H$ = Hall ...
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22 views

The speed of electrons moving in different medium

Can one have a simple (dimensional-analysis) model to evaluate the speed of electrons moving in: (1) a copper wire (2) a silver wire (3) a gold wire (4) a semiconductor wire let's use meter over ...
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Replacing diode in circuit analysis?

While analyzing circuits containing diodes in reverse bias I replace it with a pure insulator for simplifying things. Similarly can I replace a forward biased diode with a conductor and a varying ...
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68 views

How does temperature affect an electrical current

Synopsis I have read an interesting article J. Halderman et al. "Lest we remember: cold boot attacks on encryption keys" in computer science regarding cold booting. The paper discusses how the use ...
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In k$\cdot$p theory, how does one calculate the bulk inversion asymmetry coefficients given in table 6.3 in Winkler?

In k$\cdot$p theory, how does one calculate the bulk inversion asymmetry coefficients given in table 6.3 in Winkler? Winkler's book on spin-orbit coupling effects is available free online. In ...
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Calculating band gap from band structure

If while calculating a band gap, the band just below the Fermi level touches the Fermi level, can we say the material is semiconducting?
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Why is it said that without quantum mechanics we would not have modern computers?

I've heard this in many quantum mechanics talks and lectures, nevertheless I don't seem to grasp the idea behind it. What I mean is, at which point is that our modern understanding of quantum ...
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Ionization energy of a donator impurity in Si vs H ionization energy

Why is the ionization energy of a donator in an $\mathrm{Si}$ semicondutor much smaller than in an $\mathrm{H}$ atom?
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Semiconductor doping and conductivity

Why is the conductivity of Si dopped with P and As much bigger than the conductivity of Si dopped with In and P?
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Optical mode leakage through a layer of gold

The geometry of my semiconductor device is given below. The blue regions are gold, the grey ones - gallium arsenide (n-doped to $2.9 \times 10^{15} \mathrm{cm^{-3}}$). The dimensions are μm, i.e. it ...
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2answers
156 views

Reverse bias P-N junction

I am not able to understand why the PN junction does not conduct when reverse biased. Can't electrons travel from the N side through the power supply to the P side where they can jump from one hole to ...
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49 views

Working of a phototransistor

Can anyone explain how photogenerated current in the base gets amplified in a phototransistor. If you use band energy diagram, then I would understand more quickly and clearly.
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99 views

How can I simulate a model electronic hole?

Suppose I can solve time-dependent Schrödinger equation for several 1D particles (currently 3). I'd like to see, what an electronic hole is and how it behaves — in a series of numerical experiments. ...
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3answers
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How does temperature affect photovoltaics (PV) efficiency?

I know that photovoltaic panels are more efficient at lower temperatures: As the temperature increases, the output voltage decreases. I am looking for an explanation of the mechanism behind this ...
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2answers
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Why isn't there a potential difference across a disconnected diode?

I know this question sounds silly, as if there was a potential difference a current would be created when the terminals are connected together and this would mean energy has come from somewhere. The ...
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Possible to calculate carrier lifetime with doping concentrations?

I'm working on a problem involving a silicon semiconductor. A PN junction is created with $N_a = 5\cdot10^{14}$ throughout the entire semiconductor, and is doped with $N_d = 2\cdot10^{15}$ on the N ...
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230 views

The skin effect and the reflectivity of gold

I am simulating a waveguide in COMSOL, a FEM solver. My model looks like this (it is similar to a standard Quantum Cascade Laser geometry): Therefore there is a very thin (30nm) layer of gold ...
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64 views

CCD's and the photoelectric effect

Do charge coupled devices as found in telescopes use the photoelectric effect if not what eles librates the electons. Also what is charge intergration in reation to CCD's.
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Is the valence band neutral?

While studying about band theory of semiconductors, I observed that when the electrons were excited from the valence band to the conduction band, they left behind holes in the valence band. From my ...