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)

0
votes
0answers
10 views

Conductive n-type material in pn junction

I'm interested in this question from the point of view of a solar cell. In a pn junction (example, p: CIGS, n: CdS), when the n-type material is very conductive, why will the junction not be ...
0
votes
0answers
25 views

Why for each electron – hole recombination, an electron from the negative terminal of the battery is released

Why for each electron – hole recombination, an electron from the negative terminal of the battery enters the N-region and then drifts towards the junction?
1
vote
0answers
16 views

Intersection of $\rho_{xx}$ and $\rho_{xy}$ in Drude magnetotransport

Okay, so I've recently been working through the rather elementary derivation of the Hall effect in a 2 dimensional electron gas, using the Drude model. The idea is that with an E field in the x ...
0
votes
0answers
5 views

Differences between Metal-Bridge-Metal system and Donor-Bridge-Acceptor system

What is the real difference between Metal-Bridge-Metal system and Donor-Bridge-Acceptor system? In MBM there are anchor groups between the molecule and the metal electrode, can’t the groups act as ...
0
votes
1answer
24 views

What causes depletion layer to form?

I am trying to understand why and how a depletion layer forms between a P type and N type semiconductor. Before putting into contact a P type and N type semiconductor, both are electrically neutral. ...
2
votes
0answers
22 views

Van der pauw method for an isolated hole

Van der pauw method is a way to measure the resistivity of a material with arbitrary shape while it meets some specifications ( being homogeneous and ...). One of the conditions is that the sample ...
0
votes
0answers
27 views

Selection rules in a finite quantum well

I have a finite quantum well made of two different semiconductors with different bandgaps and I want to calculate the different transitions between the energy levels possible that I calculated in that ...
6
votes
1answer
588 views

How is a CCD able to collect images in drastically different lighting conditions?

I have read the basics of how a digital camera works. As much as I have understood, the digital cameras have a device called a CCD on which photons coming from the lens are incident. The CCD then ...
0
votes
3answers
29 views

Why are holes in p-type semiconductors considered positively charged?

This makes no sense to me and i think it's more of a convention. Even though we prefer talking about holes that are the majority carriers in p-type semiconductors, they have no charge and are not ...
0
votes
1answer
26 views

How to use Anderson's rule to construct band discontinuities in heterojunctions

I'm having some trouble in applying Anderson's rule to get a crude approximation for the band diagram of heterostructures. To make it more specific, I'm considering a donor-doped AlGaAs layer on top ...
1
vote
2answers
33 views

How do we get a 2DEG in a remote doped heterostructure?

I have a question regarding the way in which one often constructs a two-dimensional electron gas in heterostructures. I have a specific example in mind, although I believe this is quite a common way ...
0
votes
1answer
39 views

Where does the lowered effective mass of electrons come from?

It is a known fact that electrons in the conduction band of a semiconductor can (in certain scenario's) be described as having an approximate parabolic dispersion relation of the form $E_c(k) = E_c + ...
1
vote
1answer
31 views

Why do we have heavy and light hole bands in semiconductors?

On the topic of the valence band of a semiconductor (in this example GaAS), it is the case that the valence band has some structure to it. As shown in the illustration below, we see that at the ...
0
votes
1answer
37 views

Why are holes the majority carrier in P-Type semiconductor?

It is said that P-Type semiconductors' majority carriers are holes. But based on my current understanding, there should be no extra holes except for those generated by heat (i.e. electron-hole pairs ...
0
votes
0answers
33 views

Diode's volt-ampere characteristics

The Problem is that If the reverse saturation current is $10\ \text{nA}$ ($1\ \text{nA}=10^{-9}\ \text{A}$), Calculate the forward current while the forward voltage is $0.6\ \text{V}$. And explain ...
0
votes
0answers
15 views

Analogy in combination of batteries in series and pn junction diode circuit to find potential difference

Can I use the analogy of combination of two batteries to get the potential difference between two points in case a pn junction diode is used in the case of other battery? In doing so what is the basic ...
1
vote
2answers
29 views

Semi conductors (holes and electrons)

The following relation is mentioned in my text book for semiconductors in thermal equilibrium. $$n_e ×n_h = n_i^2$$ $n_e$ stands for the number of electrons. $n_h$ stands for the number of holes. ...
0
votes
1answer
16 views

Does drift current eventually stop in a p-n junction?

According to the Wikipedia's graph of electric field in a p-n junction, there is no electric field outside the deletion region and hence no minority charge carriers move into the other side. Also, the ...
0
votes
1answer
27 views

What does it mean that an electron-hole pair is the fundamental unit of generation?

I wasn't certain to post this in chemistry or physics section. I was reading the wikipedia article on "Carrier generation and recombination" and in the second paragraph it says something that I ...
1
vote
0answers
22 views

How do electrons move across depletion region in npn transistor? [duplicate]

Concerning the base-collector barrier, the electrons coming from the emitter move through the barrier using diffusion mainly and drift. Does carrier injection happen as a result of these two ...
0
votes
0answers
21 views

Cookbook recommendation for finite element semiconductor simulation possibly using Sentaurus

I've started work for my master's thesis using Synopsys Sentaurus for simulation of semiconductors. I'm interested in the device simulation, that is the physics, not the process simulations. The ...
1
vote
0answers
9 views

Simulate Band Bending and Band Alignment in Semiconductors

Are there softwares (simple ones preferred) where we can simulate the band alignments and band bending of a p-n junction, where we can vary properties of the junction materials such as carrier ...
1
vote
0answers
15 views

semiconductors-band theory [duplicate]

How conduction happens with the conduction band electrons? I mean does the electrons which are responsible for the conduction of holes(by just moving from one atom to other) are those which are ...
5
votes
2answers
108 views

Why are only Group III & V elements used for doping?

Only group III & IV are used for doping in elemental semiconductors like Si and Ge, why can't other groups be used instead?
0
votes
1answer
51 views

What are the current carriers in a PN junction?

Imagine a PN junction in forward bias mode. The conventional current goes from the p-side to the n-side. However, as mobile holes move to the n-side, aren't there mobile electrons on the n-side which ...
4
votes
1answer
90 views

Electron with position-dependent effective mass in magnetic field - non Hermitian Hamiltonian?

In semiconductor heterostructures it is important to treat the case of position-dependent effective mass. The (mostly) accepted form of kinetic energy operator in this case is: $$ \hat{T}=- ...
1
vote
1answer
40 views

Bandgaps of Silicon and their application in active optical elements

I know that silion has an indirect bandgap at $E = 1.12 \, eV $ or $ \lambda = 1.107 \, \mu m$ and I have read that active optical processes like absorption and emission have a decreased likelihood to ...
1
vote
0answers
103 views

what is the theoretical reason behind the new paper, Highly tunable hybrid metamaterials employing split-ring resonators built using graphene?

A few days ago, a group of University of Exeter physicists published a paper titled: Highly tunable hybrid metamaterials employing split-ring resonators strongly coupled to graphene surface ...
2
votes
0answers
35 views

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: ...
0
votes
0answers
13 views

What do you actually mean by DC current gain and a AC current gain in transistors [duplicate]

What do you actually mean by DC current again and AC current gain? I know there for formulas but I did not understand what actually they are , what is the significance. So basically I do not ...
2
votes
1answer
37 views

Why does small change in Base current causes a larger change in collector current in case of transistors? [closed]

Why does small change in the base current causes larger change in the collector current. That is say if I increase the base current buy a small amount why the collector current increases by a very ...
1
vote
0answers
27 views

Luminous Efficacy problem for LED. Semiconductor Physics [closed]

You have a white light LED with 100 lumens/W luminous efficacy when biased at 100 mA  and 0.8V.  Assume the diode has ideal characteristics and that luminous flux is linear with  diode current (a ...
0
votes
0answers
59 views

Exact (quantitative) definition of “knee” and/or “cut-in” voltage?

Sort of a 2-part question: 1) I know they are used interchangeably but are the "knee" and "cut-in" voltages of a diode actually the exact same thing? I had thought that the "cut-in" voltage was ...
0
votes
0answers
16 views

How to escape freeze-out effects of semiconductors in very low temperature

In very low temperature, semiconductors suffer from freeze-out effects. I did see that degenerately doping eliminates freeze-out, but degenerate semiconductors behave like metals. Is/can there ...
0
votes
0answers
18 views

Do equalized Fermi Levels imply zero concentration gradient?

The explanation of a P-N junction says that the Built in Voltage opposes the continual diffusion current leading to a net current of 0. What i don't understand is how there can be continual ...
0
votes
2answers
42 views

Why do we need Diffusion currents to explain semiconductor current flow?

Why do we need the idea of carrier concentrations to explain current flow? Can we simply not associate the disparity in carrier concentrations between two samples to a disparity in relative charge ...
5
votes
1answer
464 views

Why is photodiode made reverse biased?

If only its purpose is to create an additional electron-hole pair,then why would it be made reverse biased.We can good amount of current in forward biased condition.
0
votes
0answers
27 views

Zero Hall coefficient for semiconductors

Is it possible to dope the semiconductors in a way that their hall coefficient is zero?
0
votes
0answers
12 views

Hall coefficient for semiconductors

I read somewhere that hall coefficient for intrinsic semiconductors is zero. But how is that possible because the mobiliities of holes and electrons are never the same?
0
votes
0answers
11 views

Is it possible to select a single carrier type in a photodiode?

I have been reading about avalanche photodiodes and understand that they work via the impact ionization process to produce internal gain in the diode before the signal is read. It appears that ...
0
votes
1answer
31 views

Is Zener Breakdown a special case of Avalanche breakdown?

I was wondering if Zener Breakdown is a special case of Avalanche Breakdown which just works at a lower potential due to heavy doping.
0
votes
0answers
11 views

Is it posssible to numerically simulate a metal layer the same way as a semiconductor one

I need to simulate a schottky junction device. Unfortunately, the software for simulation (AFORS-HET) doesn't allow adding metal (I need to simulate aluminum contact) layers (but it allows to add ...
0
votes
0answers
28 views

Resistance of a diode

A diode is represented by an EMF equal to the electric field in depletion zone plus a resistance. This resistance is obtained from the I/U characteristic of a diode. My question is, this resistance is ...
2
votes
1answer
38 views

Doped semiconductor: “what if all donated electrons are gone?”

I have trouble understanding conductivity of a n-doped semiconductor in the band theory. I know that donator atoms carry one excess electron that can enter the conduction band easily. If this ...
1
vote
2answers
88 views

White Laser Light

I have heard that recently researchers have developed white laser light by combining semiconductor laser sources of different colors. However, I have heard that before these lasers become a practical ...
0
votes
1answer
30 views

Why dopant energy levels differ from one material to another?

Dopant levels in Si, Ge and GaAs are very different from each other. Even "similar" materials such as Si and Ge exhibit different dopant energy levels. (source: Pierret, Advanced Semiconductor ...
0
votes
1answer
33 views

Depletion region (PN Junction) question

So I understand P and N type semiconductors and the depletion region makes sense. http://hyperphysics.phy-astr.gsu.edu/hbase/solids/pnjun.html (using this as reference for my question). So the ...
1
vote
0answers
13 views

What is the use of diode? [closed]

I am confused about the use of diode. As I am look into the use of diode in Wiki, it mentioned one of its use is to be a component of rectification circuit. But will it cause damages to the diodes if ...
0
votes
1answer
61 views

p-n diode, Power as a function of the logarithm of the circuit resistance

in a circuit comprised of p-n diode and with characteristic Ohmic resistance making the diode's resistance negligible , we have for the current passing through the diode $I=I_s(exp(Ve/kT)-1)$ where ...
1
vote
1answer
38 views

Why Solid Insulators have highest breakdown voltage?

Why does solid insulating materials have a higher breakdown voltage when compared to that of liquids and gases? Can anyone explain this in simple words?