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.

learn more… | top users | synonyms (2)

-1
votes
0answers
14 views

Difference between fermi energy level in metals and semiconductors

It is not exactly a question its a kind of confusion ... Here my confusion starts... what is meant by Fermi energy level?? The only definition that i found was the energy level at which the ...
0
votes
0answers
5 views

How do i calculate leakage current in passivation layer of GaN HEMT?

I want to calculate the leakage current between the passivation and encapsulation layers of the GaN HEMT which will give me information about the material
0
votes
0answers
17 views

Which is better conductor silicon or germanium and why and also which has more band gap and why and what affects the band gap in material?

want to know on what factors energy band gap depends upon.as per me it is due to electron-proton attractive forces but according to this germanium should have higher gap than silicon but germanium has ...
0
votes
1answer
40 views

Total chemical potential of electrons in pn junction

I am reading this page about electron energy concept terminology. I am trying to apply that for the pn junction in equilibrium below. Could anyone help me to see if I get it correctly? C = ...
0
votes
0answers
23 views

Existence of eigenstates in type III staggered semiconductor heterojunctions?

Two semiconductors are aligned in the type III staggered fashion and sandwiched in between infinite potentials. Can there be an eigenstate across the valence band of one material and the conduction ...
0
votes
1answer
59 views

Density of states from $k$ to $E$

Speaking about Quantum mechanics, considering the "particle in a box" condition as an approximation of the electrons condition in a semiconductor, let the material be represented by a volume $V$ with ...
0
votes
1answer
51 views

Fermi Dirac distribution and degenerate energy states

In Quantum Mechanics and in semiconductor materials, the number of electrons $N$ in conduction band is usually computed as follows: $$N = \int_{E_c}^{+\infty} g_c(E)f(E)dE$$ where $g_c(E)$ is the ...
0
votes
0answers
30 views

Why a positive voltage raises the potential energy of a positive charge and lowers the energy of a negative charge?

I am reading the relation between energy diagram and V, E (electric filed) in a semiconductor from the site (page 47-48). However, I don't quite understand this sentence below. Could anyone explain ...
0
votes
1answer
39 views

Do energy levels such as $E_c$, $E_v$ have negative values in semiconductors?

In energy band diagram of a semiconductor, do energy levels such as $E_c$, $E_v$ have negative values? Also, why electrons in semiconductor have energy? What is the formula for energy of an ...
0
votes
0answers
14 views

Energy-band diagram of forward-biased pn junction

When a p-n junction is forward biased then its energy-band diagram looks like this: What would happen if $V_a>V_{bi}$? ($V_{bi}$ is the built-in potential and $V_a$ is the externally applied ...
1
vote
1answer
27 views

Applying a voltage to a homogeneous semiconductor

Imagine that there is a homogeneous semiconductor (either a p-type or an n-type, but just one of them) uniformly doped. There is no diffusion current because of the uniform dopage, and there is no ...
1
vote
1answer
39 views

Bands in semiconductors: $E$ vs. $k$ diagram

I always thought that in a semiconductor there was one gap, one conduction band and one valence band. However, reading a book I came across this picture And now I'm very confused. Apparently there ...
0
votes
1answer
26 views

How SPAD work over Break Down voltage?

SPAD (Single Photon Avalanche Detector) works beyond Breakdown Voltage which is mentioned as Geiger Mode. But how this actually working. When bias voltage aceede breakdown voltage, generally high ...
2
votes
0answers
40 views

Why does Fermi Level change due to change in donor atom concentration?

Suppose I have a n-type semiconductor whose fermi-level lies (say) 0.2 eV below the conduction band. Why would this level change if I changed the doping by making the donor concentration (say) 4 times ...
1
vote
1answer
29 views

Why the direct band gap semiconductor get higher optical absorption coefficient than indirect band gap semiconductor

I can understand that direct band gap semiconductor doesn't need phonon to absorb light. But in the following formula: Optical absorption coefficient is proportional to the square of hv in indirect ...
1
vote
1answer
20 views

Non-constant Bandgap in a semiconductor

For a material made of two different intrinsic semiconductors (SC); $SC_A$ on the left, and $SC_B$ on the right, such that $E_{gap,A}>E_{gap,B}$, the energy band diagram would look like so: Note: ...
0
votes
0answers
33 views

Green LED Forward Voltage

Yesterday in lab, we were asked why all of our green LED had large forward voltage than expected. We expected for the forward voltage to be at around 2.1V as according to hf=Egap=eV. Yet, we ...
1
vote
1answer
25 views

Is the intrinsic carrier concentration for semiconductors an average value?

I am learning about intrinsic semiconductors, and have just come across the intrinsic carrier concentration equation - $n_{i}=BT^{3/2}e^{\cfrac{-E_{g}}{2kT}}$ Which is supposed to give the number ...
0
votes
0answers
14 views

Measurement of Quantum Hall Effect

I'm somewhat confused about the original measurement of the QHE in a Si-MOSFET, which might stem from my not understanding MOSFETs very well. In their measurement, von Klitzing et al. measure the ...
-3
votes
1answer
30 views

Data transmission in optical fibers

Im reading though my Network Architecture lecture notes and it states optical fibers need a repeater every >10km. Repeaters are used to amplify digital signals but the notes do not explain or state ...
0
votes
2answers
39 views

Fermi-Dirac distribution - holes and electrons

The density of probability of an energy state $E$ being occupied by an electron is $$f(E,T)=\frac{1}{1+e^{\frac{E-E_F}{kT}}}$$ and the density of probability of an energy state being occupied by a ...
3
votes
1answer
47 views

How to calculate number of degenerate states?

For example if we need to get number of degenerate states for a particle confined in a 3D box that have energy $$E=41\frac{\pi ^2 \bar{h}^2}{2m_e L^2}$$ I know that $$E=\frac{n^2 \pi ^2 \bar{h}^2}{2 ...
0
votes
0answers
25 views

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 ...
0
votes
0answers
18 views

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, ...
0
votes
2answers
26 views

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?
0
votes
0answers
10 views

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. ...
5
votes
1answer
142 views

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 ...
0
votes
0answers
31 views

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 ...
0
votes
2answers
65 views

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 ...
1
vote
0answers
20 views

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 ...
1
vote
1answer
29 views

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 ...
1
vote
0answers
12 views

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 ...
0
votes
1answer
24 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?
1
vote
1answer
21 views

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 ...
0
votes
0answers
8 views

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?
1
vote
0answers
15 views

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 ...
1
vote
0answers
25 views

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 semiconductors,...
2
votes
1answer
33 views

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 ...
1
vote
3answers
112 views

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 ...
0
votes
0answers
15 views

Semiconductor physics resonant tunneling diode

What happened if the barrier in resonant tunneling diode is of unequal width?
14
votes
4answers
1k views

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 $10^{3}~\frac{\text{S}}{\text{cm}}$. ...
1
vote
1answer
19 views

Semiconductor nanostructure and heterostructure

What is the difference between compositional superlattice and doping superlattice?
0
votes
0answers
25 views

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. ...
0
votes
1answer
24 views

Is possible to excite semiconductor with attosecond laser pulse [closed]

Is possible to excite semiconductor with attosecond laser pulse for generation THz wave?
1
vote
0answers
36 views

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 ...
4
votes
1answer
70 views

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: ...
0
votes
1answer
49 views

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 ...
0
votes
0answers
14 views

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?