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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Mixed Neumann/Dirichlet BCs in Poisson-Schrodinger self-consistent solver

I'm currently in the process of writing a self-consistent Schrodinger-Poisson solver for a device heterstructure (High Mobility Electron Transistor). I am having a few difficulties however. It seems ...
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Simple calculation example of Fermi level pinning at metal-semiconductor interface

I'm having trouble calculating the following example (taken from Jasprit Singh: Semiconductor Devices, Basic Principles; John Wiley and Sons, Inc., 2001; p. 255). "Assume that at the surface of GaAs, ...
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P-n junction diode under forward bias configuration

Why there is exponential growth in current with respect to voltage in p-n junction diode under forward bias configuration?
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Diode Circuit analysis [migrated]

how can i solve circuits like this ?! how current flow though determine the diode modes and calculate V and current in branches
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BJT transistor as an amplifier [migrated]

I'm confused about a couple of things concerning the transistor.. is Vcc the signal to be amplified or Vin? And does the transistor actually amplify the voltage fed to it or does it just regulate how ...
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How long is the surface migration length of adatoms deposited by thermal evaporation in vacuum?

The deposition of metals through thermal evaporation involves the process of adatoms migrating on the substrate before its kinetic energy decreases to a certain point or before encountering a cluster. ...
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In semiconductor devices, why is quantum tunneling “fast”?

I'm reading up on semiconductor devices that rely on quantum tunneling, such as the tunnel diode and the TFET. The big advantage of these devices is apparently that "quantum tunneling is extremely ...
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What is space charge Capacitance of diode?

Most of the books say that $p$-type and $n$-type materials of diode act as parallel plates of space charge capacitance were as the depletion charges (uncovered) act as dielectric. Then why do these ...
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Electronics book for physics undergraduates

I am going through very hard time studying electronics, I studied little electronics at high school (what is diode, transistor, etc). Now in clg now I need electronics to study, I don't understand ...
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How to estimate the heat generation and the power per square cm provided the resistance and the current of a laser diode?

Laser Diodes are very tiny. So, it is making me confused in its calculation. In laboratory, the resistance of a laser diode is 10-15 ohm and the current is 80-100 mA. How could I estimate the heat ...
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Working point of a transistor circuit [migrated]

I've stumbled upon this problem which involves a circuit with 2 transistors that are connected to each other. I'm trying to find a) the "working point" ($V_{ce}$, $V_{be}$, $I_c$, $I_b$) of each ...
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How does the current flows through the collector-base junction of an NPN transistor operating in saturation? [migrated]

From what I understand, in the saturation mode of NPN transistor, both EB and CB junctions are forward biased. Now, if the voltage across CB causes it to be forward-biased, how does the current flow ...
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How to make a monocrystalline silicon seed

I do understand that you can grow monocrystalline silicon from an initial seed but I'm lost in a chicken versus egg situation where I don't understand how you can get the seed if the only way to make ...
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How does one go about designing a substrate heater for PVD? I need to design one that can go till 1000 C in Oxygen.

Can I just use a Kanthal wire and make a pattern on a ceramic base? Wouldn't such an exposed element get shorted when I use substrates like Silicon? But wouldn't a layer of ceramic on top of the ...
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23 views

How can excite a semiconductor to make a photon just by heat in room temperature?

I want to know if a semiconductor in room temperature can excite by heat, producing photon, without any other source of energy?
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How is it guaranteed that electrical connections could be made without destroying a diode laser?

A diode laser is a tiny diode and requires a microscope to see it. Since a laser generates a good amount of heat, the diode should be destroyed with the produced heat. But it does not happen. but why ...
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Relation between interlayer tunneling amplitude and external potential in Bilayer graphene

What is the relation between interlayer tunneling amplitude ($\gamma_1$) and external potential applied ($U_{ext}$)? Is there any mathematical relation?
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Why the bandgap of inorganic semiconductors decreases with temperature?

The temperature dependence of the energy bandgap in inorganic semiconductors is given by $$E_g (T) = E_{g,0} - \frac{\alpha T^2}{T+\beta}$$ where $\alpha, \beta$ are both positive, and the (somewhat ...
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what is the effect of temperature on the resistance of a photoconductor?

As we know, for a photo conductor resistance tends to decrease with increase in irradiance, but with greater irradiance comes greater temperature. Also we know, photo conductors are ...
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How does negative power lead to amplification?

I am currently investigating semiconductor superlattices and I am analyzing the negative differential velocity (NDV) after a certain limit. I understand how NDV leads to negative power, but I am ...
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Why is $np$ always equal to $n_i^2$?

For you guys who studied semiconductor physics must be familiar with the equation: $$np=n_i^2$$ I can understand why this is true for the intrinsic case (the broken bonds would always provide ...
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BEEM and Doping of semiconductors

When using Ballistic electron emission microscopy(BEEM) to Image a metal/Semi-conductor interface would applying n-type doping aide or prevent a BEEM current to be detected as BEEM works on the ...
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Semiconductor physics resonant tunneling diode

What happened if the barrier in resonant tunneling diode is of unequal width?
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Are insulators and conductors arbitrary categories?

I have seen charts showing the transition from insulator to semi-conductor is at $10^{-8}~\frac{\text{S}}{\text{cm}}$ and between semi-conductor and conductor is $10^{3}~\frac{\text{S}}{\text{cm}}$. ...
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Semiconductor nanostructure and heterostructure

What is the difference between compositional superlattice and doping superlattice?
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What is the physical meaning of potential energy in a band diagram of a semiconductor?

According to this slide (from this website), the potential energy of an electron in a semiconductor is defined by the difference between the Energy level of the conduction band and the fermi level. ...
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Is possible to excite semiconductor with attosecond laser pulse [closed]

Is possible to excite semiconductor with attosecond laser pulse for generation THz wave?
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How Does Silicon Surface Barrier (SSB) radiation detectors work?

I'm dealing whith some old detectors (about 1980) called Silicon Surface Barrier, searching online I've seen that they consist on metal-semiconductor(Si n-type) junction (schottky diode) and in one ...
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What are the phenomena responsible for irreversible increase in entropy?

https://www.quantamagazine.org/20140416-times-arrow-traced-to-quantum-source This article says that entanglement drives the arrow of time of increasing entropy towards thermodynamic equilibrium: ...
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Why can't a reverse biased diode conduct by majority carrier injection (UPDATED)?

I know that the question "why can't a reverse biased diode conduct" has been asked before (here and here), but I'm asking it from a bit different perspective. Why can't we inject electrons into the ...
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Problem in resonant tunneling diode (RTD)

What happen if the two barrier width in RTD are not same? How the transmission coefficient change for this? How the dips are formed in the transmission coefficient graph?
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Dopants vs impurities

The question is related to terminology. What is the difference between dopants and impurities in condensed matter (semiconductor) physics?
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What dictates the range of EM radiation which can be produced by semi-conductor excitation (like LEDs)

Exciting semiconductors such as silicon carbide and gallium nitride can cause electroluminescence. I believe that by altering the chemistry of the semiconductor, you can alter the wavelength of the ...
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What is the potential difference across a disconnected diode? [duplicate]

I think potential difference across disconnected diode should be zero but how? the last graph tells that there is a potential difference between the two ends of a diode. then how can be it zero?
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Does the Schottky Barrier only happen at Metal Semiconductor Interfaces?

Most references that I have come across refer to the Schottky Barrier in the setting of Metal and Semiconductor Interface. Would it be correct to use the term Schottky Barrier to refer to the mismatch ...
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How does a CCD able to differentiate between different colors?

According to Wikipedia, Digital color cameras generally use a Bayer mask over the CCD. Each square of four pixels has one filtered red, one blue, and two green [...]. The result of this is ...
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Superluminescent LED [closed]

How do Superluminescent LED generate amplified spontaneous emission? Moreover," a superluminescent LED combines the spatial coherence of a laser diode and the temporal incoherence of an LED. " Please ...
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Obtaining a Positive Hall Coefficient for Electrons Near the Top of a Valence Band

Using a Drude model of charge carriers with a charge $q$ and a mass $m$ (which I allow to take either sign at this stage) in a sample with an applied electric field $\mathbf{E}$ and magnetic field ...
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Derivation of Einstein's relation in Drift Diffusion model for Semiconductors

I'm currently reading Semiconductor Devices: Basic Principles by Jasprit Singh. In this book he gives a derivation of the Einstein relation for the Drift Diffusion model of semiconductors, supposing ...
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How many valence bands does Silicon have?

I can't seem to find a concrete answer anywhere online. I am under the impression there are three valence bands before the energy gap in Silicon? (As opposed to Ge, in which there are 4?) Any help ...
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The width of the space charge region in a pn-junction

Given a pn-junction as in the picture below. Which quantity determines the width of the space charge region? Or in other words, why don't the electrons in the n-doped region wander towards the ...
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Calculate 2D Effective mass from bulk effective mass

I am trying to create a self consistent Shrodinger Poisson Solver for various semiconductors. There is already one done by Professor Hu from UC Berkeley - QM CV Simulator. Looking at the code, they ...
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The probability of photoluminescence

Was reading about premeditated doping in semiconductors and the effect it imposes on the emission spectrum, doping as I read introduces defect states which are close to either the valence band edge or ...
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Semiconductors, Solid-State Physics

We know, that conductors, conduct because their valence energy band is "half" full, and k ("wave vector") can increase and therefore the electrons under the influence of a electric field can "move", ...
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electron blocking layer and hole blocking layer

What is basically an electron blocking layer and a hole blocking layer in contrast to an electron transport layer or a hole transport layer? In terms of the bandgap, I think if the case is one of a ...
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Measuring the effective mass

Intro: To avoid any terminology confusion, this is asked in the context of Solid State Physics and semiconductors. The canonical definition given for the effective mass is that it is related to the ...
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What happens after an electron and hole combine?

OK so I understand that an LED is a pn junction where when a forward bias is placed across the junction, the electric field causes the electrons to combine with the holes and release a photon through ...
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Electron jump into a transistor to read qubit state

Prof. Andrea Morello, a quantum physicist, in one of its quantum computer models uses the spin of the outermost electron in a phosphorus atom to represent a qubit. This atom is embedded to a ...
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Liquid conductors and conservation [closed]

Would gas or liquid conductors cost less than metal and are they more efficient conductor? Is there a material that would contain a magnetic field and would it increase conductivity? If so, This ...