Questions tagged [semiconductor-physics]

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 harness it in electrical circuits.

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How does one measure effective mass in a multivalley semiconductor?

I understand the answer given in this question. It explains how we can measure the effective mass in a semiconductor. However, I wonder what happens in the case of a multivalley semiconductor. Namely, ...
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How does annealing improves the ohmic contact?

Suppose we have a p-type material and metal contacts deposited taking the work function of a metal and semiconductor into account. At room temperature (depending on the doping level) they might now ...
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How can an $n=25$ Rydberg state exist in a solid? What does the wave function look like?

Phys.org's April 15, 2022 Ancient Namibian stone could hold key to future quantum computers begins: A special form of light made using an ancient Namibian gemstone could be the key to new light-based ...
uhoh's user avatar
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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 an exciton only observed when we excite to the conduction band and not to other electronic level inside the bandgap?

Excitons can be observed when we excite electrons to the conduction band. I don't know about excitons being observed when we excite the electrons to an electronic level that would eventually be in ...
cinico's user avatar
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Can an LED emit photons with energy (in $\rm eV$) larger than the voltage drop across it (in $\rm V$)?

I recently had a discussion with someone who told me that they have a UVC (260 nm - 270 nm) LED with a forward voltage of 3.3 V. I told them that this must be impossible, because an electron dropping ...
MaxParadiz's user avatar
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Books recommendation to understand Quantum Confined Stark Effect

I am starting a PhD on a photonic component involved with QCSE. The problem is that I have a Master degree in electronical engineering, not in fundamental physics, and I need to understand the QCSE in ...
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Why does Ashcroft and Mermin say an acceptor level in a semiconductor cannot be empty, only singly or doubly occupied?

On page 581 of Ashcroft and Mermin, Solid State Physics: Acceptor Level In contrast to a donor level, an acceptor level, when viewed as an electronic level, can be singly or doubly occupied, but not ...
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Why bulk of HPGe detectors is doped?

When I am looking at schematic diagrams of HPGe gamma spectrometer detectors (like this Ortec GLP one), it is often mentioned that bulk of Ge is doped. In this example - P-type doped. Is there a ...
BarsMonster's user avatar
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Why is the Fermi level (energy) shfited in doped semiconductors?

According to the Fermi level is shifted due to doping: Upwards in case of n-type and downwards in case of p-type. Why is this? The Fermi level is the level where the probability that an electron ...
Ben's user avatar
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Why the product of hole and free electron density is constant in semiconductor?

I have learned from a text book of electronics that the free electron density, n (which is equal to that of hole, p) of intrinsic semiconductor due to thermal excitation is a function of temperature ...
Sabbir Ahmed's user avatar
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Potential drop across PN junction diode in forward bias

If a PN junction diode is connected to a battery, the P part must have a higher potential than the N part(because these points are connected to the battery) and so there should be a potential drop ...
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Different Color Intenensities from simple ON/OFF RGB subpixels

I recently got interested in electronic paper. One design that I liked was the one from Mirasol: https://en.wikipedia.org/wiki/Interferometric_modulator_display However, what I don't understand, is ...
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What is a Fermi arc?

What is meant with a Fermi arc in the context of Weyl semimetals? Is this the just a one-dimensional Fermi surface? For example, in electron-doped graphene, the Fermi surface consists of 2 disjoint ...
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What is the true quantum description of electron transport in solids?

Im currently struggling to understand the quantum description of electrical current in a solid. Applying the linear combination of atomic orbitals and applying the Bloch theorem we can get different ...
terminate's user avatar
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Electron movement in valence band

I'm getting very confused about the movement of electrons in the valence band. In the textbook I'm reading, the convention is that these electrons have a negative effective mass. Therefore, when a ...
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What's a typical lifetime for excitons, or biexcitons?

I've read that a typical lifetime for excitons in a semiconductor is 1-10 picoseconds. I believe these are Wannier-Mott excitons. What are typical lifetimes of other kinds of excitons, for example in ...
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What is the difference between the joint density of states and the density of state?

I think I understood the density of states, but I didn't understand the joint DOS. What is the main difference? What is the exact definition of the joint DOS? When do we use the joint DOS and when do ...
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Studying Chaos in RLD circuit

We are currently working on non-linear dynamics (chaos theory) by analysing a series circuit including a diode (the 1N4004), a 100 ohm resistor and a 20 mH inductance. It is driven by an alternative ...
tortue physics's user avatar
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Reconciling electron configuration and valence electron distribution over separate energy levels in energy band theory

This seemed like more of a chemistry question to me, but I was told by the people at chemistry.stackexchange that it might be more appropriate to post here, since "it was the physics guys that did all ...
The Pointer's user avatar
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Combined effects of strain and doping on the electronic structure of semiconductors

I've read papers in DFT studies on band gap tuning in semiconductors and the usually studied methods are either through doping or application of external strain. But its always just one or the other. ...
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What does it mean if the resistance of a semiconductor increases due to light?

I have synthesized an $n$-type semiconductor material $\text{ZnO}$. Under light illumination, its resistance keeps increasing. What are the reasons for this?
Sonia T's user avatar
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"Doping" a metal

I had my practical exams today, where I was told to explain the structure and working of a Unijunction transistor (UJT, https://www.daenotes.com/electronics/industrial-electronics/ujt-uni-junction-...
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Optical Conductivity and Scattering rate - Physical intuition

Why does the real part of conductivity increase with increase in scattering rate at frequencies much larger than the scattering rate? I understand the mathematical implication, but do not understand ...
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How to calculate Hall coefficient in gold and silver?

BACKGROUND - Hall Effect Using the free-electron model, the Hall coefficient is calculated as $$R_H = \frac{1}{ne},$$ where $e$ is the elementary charge and $n$ is the carrier density. For a metal $X$...
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What do I measure with power meter?

I modulate directly a laser diode by setting the pump current periodically from 0 A to $I_{on}$ A. I do it for different duty cycles and different frequencies. But I need to keep my average power of ...
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Two-Band k.p Model is not Hermitian for imaginary wavevectors

In E. O. Kane's original work on Zener Tunneling, he uses a two-band $k\cdot p$ model for the semiconductor bandstructure: $$H=\begin{pmatrix}E_g+\frac{\hbar^2k^2}{2m_0}&(\hbar/m)kp\\(\hbar/m)kp&...
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Two Photon Absorption dependence on Semiconductor Band Gap

It's well known that Two Photon Absorption coefficient is scaling with $E_g^{-3}$. Does anyone know what is the physical reason for this scaling? What is the physical theory behind this mathematics?
user31173's user avatar
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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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How to separate electron and hole mobilities in a intrinsic semiconductor?

I read in textbooks that the electric conductivity of a semiconductor is $\sigma=q(n\mu_n+p\mu_p)$, where $q$ is an electron's charge, $n$ and $p$ are the concentrations of electrons and holes, $\mu_n$...
Vladislav Gladkikh's user avatar
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If an atom loses electron, it becomes a cation; it does not form a hole. However, when electron is lost from a bond, it forms a hole and not a cation

If an atom loses an electron, it becomes a cation, and when an electron is lost from a bond, it forms a hole. This is what the professor told the class, but I am not able to find the reason for that ...
Logan's user avatar
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1 answer
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Extension from Excitons to Trions

I am curious about the fundamentals of how a trion state is defined. An exciton state is considered a bound electron-hole pair. This can be formed by is we have a ground state which consists of a full ...
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Understanding mixed trigger avalanche breakdown in pn junctions

I am reading a device physics text (Sze Physics of Semiconductor Devices, 3e, Chapter 2.4.3) and I am trying to make sense of the discussion of avalanche breakdown. The discussion is (over?)simplified ...
EE18's user avatar
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$\vec{k}\cdot\vec{p}$ Hamiltonian approach

I am new to reading into the $\vec{k}\cdot\vec{p}$ approach. Where for a periodic function $u_{\vec{k}}$, which satisfies the Schrodinger equation: $$ H_\vec{k}u_{\vec{k}}=E_{\vec{k}}u_{\vec{k}} $$ ...
Lb762's user avatar
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The difference between $E-k$ diagram and simplified Energy band digram

I know form the the Kroning-Penny Model the $E-k$ diagram solution which something like this or like this but While dealing with semiconductors we always draw this energy band diagram My question ...
amin's user avatar
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Have often named "applications of quantum physics" existed before the theory itself?

Many "applications" are linked to quantum physics - let it be the laser, LED's, transistors, MRI scans, atomic clocks, electron microscope or CCD-detectors in digital cameras. I wonder ...
manuel459's user avatar
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What's a good alternative to Neaman's book on semiconductors?

So I'm an EE major taking a course for engineers on introductory semiconductor physics. It's an online course with no live lectures so I'm essentially trying to teach myself, which isn't going very ...
2 votes
0 answers
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What are occupied states in a semiclassical context?

I've been reading this question and the answers it received, and I still have some unresolved questions. It is common to use the semiclassical approximation in describing charge carrier transport in ...
Dave's user avatar
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Type of energy in energy band diagram of a solid

What type of energy do the energy levels in the energy band diagram of a solid such as silicon (Si) represent? Potential energy? Kinetic energy? Or total energy? I saw in a book that kinetic energy of ...
Mahdi Masoodi's user avatar
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67 views

Shockley-Queisser limit calculations

I am working through the paper, Detailed Balance Limit of Efficiency of p-n Junction Solar Cells by Shockley & Queisser, for my own research with perovskite solar cells. I am able to follow their ...
Earthling75's user avatar
2 votes
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129 views

How does ambipolar transport work?

In my introductory semiconductor physics class, I learned that "excess holes and electrons move together in the presence of an applied electric field because of the development of an internal ...
Donghwi Min's user avatar
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376 views

Rigorous book (or other materials) on Circuits, Electronics etc

What I usually find in a typical book on these topics is the following structure: "Here is the theorem/fact/formula, here is an example - now go ahead and apply this to some trivial problems that ...
2 votes
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How to build a quantum model of a P-N semicondctor junction?

Literature for quantum modelling of a semicondunctor P-N junction seems to be almost completely absent. I am wondering is it because it is too complex or the justifications provided by classical ...
illusion's user avatar
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Total energy on island (single electron box), how to derive it?

I have a basic question about the energy of having $N$ electron on an island for the single electron box. I am following this lecture, where we have the circuit given below. $C_g$ is the capacitance ...
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Has anyone come across the relationship between Higher order confinement wave-functions and corresponding Zeeman Interaction?

I'm studying a hole quantum dot in Germanium. The problem is described in the Luttinger Spin-3/2 basis and takes Fock-Darwin states as solutions in the Quantum Dot plane(xy plane). Furthermore, I ...
Retalativity 's user avatar
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1 answer
134 views

(Too?) simple model of pn junction

I am trying to build a simple model of a pn junction in order to show high school students how it works. I am not looking for something precise, so I use really simple discretization and I discard ...
courno's user avatar
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How Does Semiconductor Vacuum Energy Change with Doping?

In the paper "The application of semiconductors with negative electron affinity surfaces to electron emission devices" negative electron affinity is defined by the condition ($E_c - E_f) >...
ElectronsAndStuff's user avatar
2 votes
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154 views

Why does Seebeck coeffcient increase with Temperature?

So I have extracted a graph for the Seebeck coefficient vs energy with at varying temperatures (Top right). However, I am struggling to understand the relationship. Why is it the increase in ...
Sajidur's user avatar
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1 answer
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Why Cannot Photons Create Electron-Hole Pairs?

My question might be dumb or considered trivial, but I will try to explain my confusion. In a Particle Physics course, we were taught that only charged particles (such as electrons $e^{\pm}$, $\mu^{\...
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2 votes
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Apart from mirrors, what other feedback mechanisms can you think of in a semiconductor laser

Today, I was asked by my professor this question. I was unable to answer it but I am curious to know about this. Apart from mirrors, what other feedback mechanisms can you think of in a semiconductor ...
Yogesh's user avatar
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