Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange
Join us in building a kind, collaborative learning community via our updated Code of Conduct.

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.

0
votes
0answers
46 views

Why is the energy required to create an electron-hole pair in semiconductors higher than their band gap energy?

I am studying semiconductor physics and in more than one book I have found that the energy needed to create an electron-hole pair in Si and Ge is a few times higher than the band gap energy. For ...
1
vote
2answers
57 views

Existence of conduction electrons in pure Si at room temperature

Silicon has a bandgap of ~1.1 eV whereas the room temperature thermal energy is ~0.04 eV. But we still find electrons in the conduction band for a pure silicon wafer, away from any radiation. I ...
0
votes
0answers
13 views

activation of donors via annealing

I've been reading up on semiconductors and quantum computing in general and have come across "activating donors via annealing" a lot, in papers such as here for example. From what I gathered, they ...
1
vote
1answer
49 views

Who controls completing the circuit in a transistor? [closed]

Consider an npn junction. The p-type semiconductor p has holes which are filled by electrons provided either by the n-type or by phosphorous dopants. The transfer of charge from n to p forms a ...
-1
votes
0answers
14 views

Laser Diode with micro lens problem

Good morning all, I am looking at using a laser diode with a micro lens already applied to the fast axis.Here are the numbers I have been given by the manufacturer: 8° Diveregnce on both axis after ...
0
votes
1answer
31 views

Mental contradiction: Valence electrons do not move at the non-zero wavevector?

I have a mental contradiction. Let's consider the following band structure with the Fermi energy somewhere inside the gap: where $\Gamma$ point represents the zero value of the wavevector $|\vec{k}|$....
0
votes
0answers
10 views

Substitution of $-E_F-E_g$ for $E_F$ in distribution function and transport integrals for holes

As far as I understand, holes occupancy governed through distribution defined as follows, $h=1−f=1−\frac{1}{e^{\frac{E-E_F}{k_BT}}+1}$ but when I tried to calculate transport coefficient involving ...
1
vote
2answers
60 views

Dark current and thermal excitation in CCDs

In charge-coupled devices (CCDs), doped semiconductors are used to produce an electronic signal from incoming photons - the underlying principle being the photoelectric effect. This simple law tells ...
-2
votes
1answer
37 views

What is the dark current in a solar cell?

What is meant by the dark current in solar cell? Is it the current obtained by applying an external voltage?
3
votes
1answer
25 views

Why is it not possible to dope semiconductors with elements with 6 or 2 valence electrons?

As far as I have learnt, semiconductors are often made using elements from the 4th group, and their properties are often enhanced by doping with either pentavalent or trivalent elements. Take the ...
0
votes
0answers
18 views

What is charge relaxation and spin relaxation in an atom/ artificial atom?

I want to understand the difference between these two terms.
0
votes
0answers
18 views

By shortening the N-type side to the P-type side of a diode with a wire, how does the electric potential looks like in each point of this circuit?

To avoid misunderstanding I'll first start with the notions. The electrochemical potential (which in semiconductors refers to as the Fermi level) is the sum of the chemical potential and electrical ...
1
vote
0answers
22 views

What the difference between pin and pn diodes i-v curve?

For my understanding there should be no big difference in i-v curve between regular p-n junction and p-i-n junction, the only difference i can think about is do to the bigger resistance of the ...
0
votes
0answers
31 views

What is the physical interpretation of energy band graph in semiconductors?

Does this graph represent energy states in a single atom which makes it into the semiconductor or is this a representation of sum total of energy levels occupied by different electrons in the lattice ...
0
votes
0answers
13 views

When Pin diode is no longer junction?

For p-i-n junction with intrinsic region d, I need to answer what happened when d is very large. So from simple logic, I believe that at some point there will be no diffusion of charge carriers from p-...
0
votes
0answers
20 views

Built In voltage drop across a pnn+ device

Will the net built-in potential of an p+,n,n+ device having two junctions(1.) that of p+ and n and 2.) that of n and n+ simply be the addition of the built in potentials of the junctions?
0
votes
0answers
19 views

Meaning of F(E)Z(E) in semiconductor theory

I really don't understand the following term $$ \int F(E)Z(E)dE$$ where $F(E)$ is the Fermi-Dirac distribution (but it could be any distribution) and $Z(E)$ is the density of states. What I really ...
1
vote
2answers
97 views

Confusion regarding Hall effect in semiconductors

In many places, it's mentioned that in hall effect, the holes move under the influence of magnetic field in the direction as shown in the figure. In this figure itself, the bound electrons move in the ...
0
votes
0answers
15 views

certain bulk structure avalanche photo diode (multiplication stage)

I've a bulk structure from a photodiode from hamamatsu. There are quite a lot explanations and so on available for a typical avalanche photodiode: Above image is from hamamatsu. Nevertheless I also ...
0
votes
0answers
6 views

Charge carrier in avalanche photodiodes

Why is the drift current/avalanche multiplication in avalanche photodiodes mainly build of electrons? And not also on holes since electrons are "always"(?) refered to electron-holes in semiconductors?
0
votes
0answers
8 views

Ballistic FET with channel made of ferromagnetic semiconductor

How do I find the characteristics, features, and differences of a standard ballistic FET (Field Effect Transistor) if the channel is made of a ferromagnetic semiconductor. Any papers/leads on how to ...
0
votes
1answer
36 views

How does a hole do impact ionization?

Impact ionization is said to be generation of electron-hole pairs with help of free electrons and holes. I have the intuition on how a free electron would be able to generate electron hole pair. I can'...
-1
votes
1answer
19 views

reverse / dark / leakage current

what is the difference between reverse, dark and leakage current of a (photo-)diode? From my current understanding it all seems to be the same?
0
votes
0answers
16 views

SiO2 layer in diodes

Can somebody please explain the purpose of this SiO2-layer? Thank you!
2
votes
1answer
51 views

Link between tunneling rate and conductivity

Generally speaking, in the theory of single-electron tunneling events (one electron tunneling through a quantum well), the rate under which this event occurs is calculated using Fermi's Golden Rule, ...
0
votes
1answer
36 views

Doping in semiconductors - location of new states

A short question relative to doping semiconductors: What defines the location of new energy states? For example, why does doping of n-type add energy states slightly below the conduction band (and not ...
-1
votes
1answer
43 views

is semiconductor in thermal equilibrium?

If a semiconductor is heated such that there is no temperature gradient, is it under thermal equilibrium? I have studied that if no temperature gradient exists across a semiconductor then it's in ...
0
votes
0answers
10 views

Impurities in HPGe crystals

Is there any way that one can find the impurities existing in an HPGe crystal? This is required for making an accurate simulation of the material of the crystal including the concentrations of Ge and ...
0
votes
0answers
13 views

Reverse barrier potential

I have studied that the reverse barrier voltage of a diode connected to a battery is equal to the barrier voltage of the diode under no bias plus the voltage of the battery. If we apply Kirchhoff's ...
2
votes
2answers
149 views

Is Fermi level located above or below donor levels in n-type semiconductor?

I find contradicting information about this. Some resources says it's above donor levels Hyperphysics website: and other say it's below, eg. on this ResearchGate thread: in n-type semiconductor,...
1
vote
0answers
24 views

Change of refractive index using semiconductor

I was wondering, if it is possible to change the refractive index of a semiconductor using an electric field or current? I have heard about injecting charges to tune the refractive index. How/Why does ...
0
votes
1answer
18 views

Change Carrier Density Of Semiconductor [closed]

Do you know how you can actively modulate the carrier density in a semiconductor ?
0
votes
1answer
35 views

How does base-emitter voltage affect the current gain of a transistor?

I'm doing a Physics project related to transistor operation. My data shows that as the base-emitter voltage drop increases, the current gain of the transistor rises and eventually plateaus at a ...
2
votes
1answer
78 views

Photoluminescence Spectroscopy- Two individual spots, different colors, but same emission spectra

my apologies in advance if I'm not posting at the right site, but StackExchange-Physics is the closest one that relates to this question. Method: Photoluminescence spectroscopy Sample being studied: ...
0
votes
0answers
16 views

Fermi Dirac probability relative to electrons and holes

I'm having a hard time to understand the following sketch: especially in case of the second diagramm. What does E against f(E) mean? How do I interpret this? The probability f(E) of an electron is ...
1
vote
1answer
27 views

band gap energy (discrete or continous?)

What does the band gap energy mean explicitly? Is it a single, discrete energy or is it a energy region? Sketches always show a "gap" between the conduction and the valence band so I assume there are ...
1
vote
1answer
55 views

Physics behind depletion region?

I was reading the PN junction. During the formation of PN junction diffusion process takes place in which the free electrons cross the boundary of the P-N and joined with the holes in the P-type to ...
0
votes
0answers
16 views

Ambipolar Transport

In Neaman, Semiconductor Physics and Devices, of the many important implications of ambipolar transport, one the author puts special emphasis on is: When an electric field is applied across the ...
0
votes
0answers
13 views

Edge Effects of an Ideal Diode

The ideal diode equation says that current changes in the quasi-neutral region as you travel across the axis. However, how do the surfaces on the perpendicular to the to flow of current affect the ...
0
votes
1answer
16 views

Conceptual doubts with quantum-confined lasers

So, I'm reading about quantum-confined lasers, and I think that I understand the majority of it, but I haven't conceptualized some things that I think are pretty basic. I'll leave this picture here as ...
1
vote
1answer
43 views

Why is there a difference between Fermi levels in metals and metal-oxide semiconductors (MOS)?

Why are Fermi levels in metals lower than the Fermi level of $\text{p}$-substrates in metal-oxide semiconductors (MOS)? Specifically, why is there a difference of $qV$? $\hspace{50px}$
0
votes
1answer
108 views

Non uniformly doped semiconductor

I am reading Neamen Semiconductor Physics and Devices. In the topic "Non-Uniformly Doped Semiconductor, the author says if there's, let's say, an N-type semiconductor that is non uniformly doped, the ...
0
votes
0answers
36 views

Wigner-Ekhart theorem for Fermi Golden Rule in semiconductors

I have seen many authors mentioning that there is a way to work in total angular momentum basis and calculate the matrix elements using the Wigner-Ekhart theorem. Here the author even says that ...
0
votes
1answer
26 views

Acceptors with very high energy level in semiconductor

I have gallium arsenide (energy gap of 1.4 eV) doped with silicon in concentration of $10^{14} cm^{-3}$ and energy level very close to the conduction band so it's act like a donor. Now we put in also ...
1
vote
1answer
43 views

What should be continuous at the interface of two materials, electric potential chemical potential or electrochemical potential?

At the interface between: 1) conductor/conductor 2) conductor/semiconductor (or dielectric) 3) semiconductor/semiconductor (or dielectric/dielectric) What quantity should be continuous? Is it the ...
0
votes
0answers
33 views

Band structure and Density of states (DOS)

Can someone explain how these two plots are related? How are the peaks in the right are associated with the left figure?
2
votes
1answer
53 views

What is the difference between electrons and holes in silicon?

Electrons and holes behave differently in a silicon semiconductor (e.g. mobility of holes is one order of magnitude smaller than that of electrons, the collection time of holes at the same electric ...
0
votes
0answers
34 views

How does ambient temperature affect material conductivity

In the book I read I found many contradiction as to how ambient temperature affect material conductivity. Here is an example: Highlighted sentences are cntradictions - "Does any termal energy create ...
0
votes
0answers
19 views

In pn diode, how does an electron flow from p to n during reverse recovery phase

During forward bias : An electron from the negative terminal of battery enters the conduction band of $n$ side, runs toward the junction, waits for a hole for $\tau$ seconds, when it finds one, it ...
1
vote
1answer
24 views

Inverse polarization of semiconductors as detectors

I've been reading the particle detector section of the PDG and in point 33.2.3 they talk about Solid-state photon detectors. They say there that Silicon Photodiodes are simply a "reverse-biased p-n ...