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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Donors/Acceptors in Metal Oxides

Can anyone explain to me why most articles describe chromium as an acceptor in titanium dioxide? In TiO2, titanium has the charge state Ti$^{4+}$ and oxygen has the charge state O$^{2-}$. When Cr ...
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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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Model for a thin metal/semiconductor junction?

Are there any books or articles that describe models for transport in a metal/semiconductor junction where the thickness of the semiconductor is less than the thickness of the depletion/accumulation ...
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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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Difference between inorganic and organic semiconductors: electronic structure or configuration, or?

Organic semiconductors differ from inorganic semiconductors. In organic semiconductors the molecules are held together by weak van der Waals interactions and in inorganic semiconductors by covalent ...
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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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100 views

Derivation of existence of energy band gap in semiconductor (solid State)

I am looking for both a mathematical and a physical reason for energy band gap in metals. For Physical reason, I was told that at each reciprocal lattice, you could have Bragg scattering, that would ...
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67 views

Fermi Energy and the Electric Potential

In an extrinsic semiconductor the electric potential is: $$\phi = \frac{1}{q}(E_{\mathrm{F}} - E_{\mathrm{Fi}})$$ where $E_{\mathrm{F}}$ is the Fermi energy, $E_{\mathrm{Fi}}$ is the intrinsic Fermi ...
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Hall effect with similar positive and negative carriers?

The Hall effect includes the transverse (to the flow of current) electric field set up by the charges which accumulate on the edges, to counter the magnetic component of the Lorentz force acting on ...
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generation / destruction of fermions by phonons

my Hamiltonian consists of 1D free fermions coupled to a bosonic bath. The interaction is dictated both by scattering terms $H^{scatt}=\sum_{kq}\alpha^S_{kq}c^\dagger_kc_{k+q}X_q+h.c.$ as well as ...
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571 views

How did the Bardeen-Brattain point-contact transistor work?

How did the Bardeen-Brattain point-contact transistor work? What are the conditions under which a Schottky barrier injects minority carriers? In a bipolar junction transistor the forward-biased ...
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86 views

Electron Relaxation/Polarization for and n-type Semiconductor

Please help me understand the following (general) statement, referring to electrons in a full valence band of an n-type semiconductor: "An electron filling up the last empty state in the valence band ...
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104 views

Why does silicon have an indirect gap?

Is there an intuitive explanation as to why silicon has an indirect gap? I have heard that this can explained using pseudopotentials.
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Semi-conductors and induced charge

Can a semi-conductor ( germanium or silicon) or a semi-metal ( graphite ) carry an induced charge ?
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838 views

Why is the valence band maximum at the gamma point in the bandstructure view of dispersion relation?

Why is the valence band maximum for most semiconductors at the gamma point in the bandstructure view of dispersion relation
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327 views

What is effective mass approximation

Currently i am studing about quantum confinement in semiconductors and came across effective mass approximation.but i am unable to understand this concept. what is the use of effective mass ...
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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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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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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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28 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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Vacancy Generation / Annihilation Time (Relaxation Time)

Vacancy Generation/Annihilation Time, Recombination Time and Relaxation Time ($\tau$) are all synonymously used in atomic physics literatures. They're defined as the time that it takes for vacancies ...
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39 views

How does a liquid crystal on Silicon affect the phase of incident light?

When a polarized light beam is directed to a phase-only LCoS system how is the phase modulated ? What is the physical effect behind ? Does voltage modulation has an impact on birefringence ?
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382 views

What is the reason behind band gap narrowing in semiconductors

I want to know why some semiconductors band gap decreases after doping with elements. Burstein-Moss band-filling effect can be useful to explain band gap widing in a semiconductor materials but i was ...
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Nature of electron states in a semiconductor

Usually one is led to think of an electron moving from the valence band to the conduction band as an electron leaving the atom it is bound to in the lattice, and becoming free to move, while leaving ...
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Is there a difference in binding energy between a regular material and a doped one?

Say Silicon and boron doped silicon. Would the doping affect the binding energy? Could I see this in an XPS spectra?
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103 views

More physical explanation of impurity energy levels in a doped semiconductor?

I'm reading about doped semiconductors in Ashcroft and Mermin. They tell you that when donor impurities are added to a semiconductor, their energy level $E_d$ is just slightly below the conduction ...
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111 views

Energy band diagram of a metal-silicon-metal device, bias voltage applied

I have an intrinsic silicon layer sandwiched in between two aluminum contacts. I'm trying to figure out the band diagram of the entire device when a positive bias (much larger than the work function ...
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88 views

What are the values of effective mass approximation

For my research work i am trying to calculate band gap of zinc oxide theoratically and found this paper (Determination of the Particle Size Distribution of Quantum Nanocrystals from Absorbance ...
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Where does the reverse current come from in a organic semiconducting diode?

Unlike traditional inorganic diodes, organic semiconducting materials hold few thermally exited free carriers under room temperature, so the reverse current should be small if pinholes of the films is ...
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1 Mohm Resistivity at cryogenic temperature for doped silicon

I would like to pick the correct doping of silicon to get 1 Mohm cm resistivity at liquid helium temperature of 4.2 K. The metal insulator transition implies that I need a very accurate doping. Are ...
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56 views

Orientation in GaAs

I can't find the precise definition of what is the orientation of a GaAs lattice. Being the superposition of two fcc lattices (one of Ga, the other of As), I would think that it is the direction of ...
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803 views

How to determine donor or acceptor impurity

I am working on a practice exam for semiconductor physics. Can anyone help me figure out how to determine whether we have donor or acceptor impurity in Gallium Arsenide? ...
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393 views

Fermi level in disordered amorphous and/or organic semiconductors

So, the Fermi level in crystals is pretty easy to understand. Been using it and talking about it in terms of the highest occupied level forever. However, I'm now reading about disordered systems. A ...
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Zero band gap semiconductors

It is known that graphene is a zero band gap semi metal. It originates from the meeting of the linearly dispersed valence and conduction bands on the Fermi level at the same high symmetry point "K", ...
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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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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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21 views

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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43 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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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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How does band narrowing (heavily doping the emitter) affect the alpha F and alpha R in the Ebers-Moll model of a BJT?

I think that when the emitter is heavily doped, the bandgap is reduced which increases the reference forward current(current flowing through the E-B junction ) but the alphas themselves do not change. ...
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Types of semiconductor relaxation

Ok, so you've basically got tensile and compression strain in a lattice mismatched material right? So as you're epitaxially layering the material, the strained material is deforming more and more ...
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P-type MOSFET performance

I was reading somewhere that the (110) plane has the highest atomic density and is best for p-channel MOSFET performance. How high atomic density influence the performance of P-channel crystal?
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364 views

The Gunn diode and the two valley theory

In today lecture of microwave and radar my teacher explained about the Gunn diode. He said it is made up of only one type of matrial e.g. $GaAS$ as shown in (a) part of the image. He said that there ...
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Confusion in biasing a NPN transistor in CE config

In CE configuration of NPN transistor, collector emitter junction is reverse biased. But how is a N-N junction reverse biased?
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121 views

Space charge limited current with and without traps

Main Question Would someone please qualitatively describe how space-charge limited conduction in oxide works, both with and without traps? I am interested in this in the context of conduction through ...
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48 views

What's the typical material used as a low-k ILD in semiconductors?

Semiconductor companies (namely IBM, Intel, TSMC and etc.) may use different low-k materials as inter-layer dielectric (ILD) in their fabrication process. I'm wondering what is the most typical one. ...
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47 views

What happens to the impinging light if its wavelength is smaller than the absorption band of a semiconductor?

Are all wavelengths absorbed in the semiconductor regardless of material's absorption band?
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40 views

What are some common errors when it comes to measuring hall voltage of a semiconductor?

What are some common errors when it comes to measuring hall voltage of a semiconductor? I've thought of two errors: Adjusting the potentiometer so that the width of the conductor would start with 0 ...
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What are the injection current and shift current?

Here is the Article that describes the injection and shift current by a phenomenological model in part II. I just read little books and articles, and do not know what the injection and shift current ...