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 affect it.

learn more… | top users | synonyms

0
votes
1answer
708 views

Constructing Tauc Plots

How can we construct a tauc plot using data from the transmission spectra? How does one calculate the absorption coefficient for plotting tauc plots?
0
votes
1answer
266 views

Influence of the temperature on the ionization energies for impurities in silicon

Is there any dependence of the impurities ionization energy on temperature in silicon? I mean if there are any interactions between localized electron and phonons which leads to renormalization of ...
1
vote
1answer
217 views

DFT for bandstructure

Density Functional Theory (DFT) is not appropriate in predicting the band gap of the materials. However, which functional gives close value to the experimentally observed band gap of semiconductors? ...
2
votes
3answers
276 views

Producing electricity from all wavelengths of electromagnetic spectrum

Is it possible to produce electricity from all wavelengths of electromagnetic spectrum beside visible light ?Like using gamma rays or x-rays .
2
votes
0answers
586 views

How did the Bardeen-Brattain point-contact transistor work?

How did the Bardeen-Brattain point-contact transistor work? What are the conditions under which a Schottky barrier injects minority carriers? In a bipolar junction transistor the forward-biased ...
0
votes
2answers
4k views

How does current flow from the emitter, through the base and to the collector in a NPN transistor?

So, I understand that for a NPN transistor to work the emitter-base junction needs to be forward biased and the collector-base junction needs to be reverse biased. I understand how current flows from ...
0
votes
1answer
342 views

Photon Absorption and Emission: Conductors v. Semiconductors

I'm having a hard time understanding how photon absorption and emission in metals (conductors) compares to semiconductors. Obviously, in SCs, absorbed photons lead to electron-hole pairs and emitted ...
0
votes
2answers
201 views

If we connect a block of p-type semiconductor only to a positive terminal, will it become positively charged?

Connect the positive terminal of a battery to a piece of p-doped semiconductor, say, silicon doped with boron. Will the terminal pull electrons out of the doped silicon, or equivalently, inject holes ...
4
votes
1answer
152 views

Semi-conductors

Suppose there is a semiconductor with Fermi energy $E_f$ and that there are $N$ bound electron states. I'd like to know why the mean number of excited electrons takes the form $$\bar n={N\over ...
3
votes
2answers
445 views

Estimation of the internal electric field strength in the pn-junction

I would like to compare my result in an order of magnitude. So, How can I estimate the strength of the electric field in a typical Si PN-junction?
4
votes
3answers
2k views

Tunneling v. Hopping

Can someone explain the difference between hopping and tunneling? The context I'm considering is conduction in semiconductors, specifically between impurity states within the bandgap. It's always ...
4
votes
1answer
299 views

Fermi level in equilibrium and non-equilibrium situations

Why do the Fermi level for electrons and holes coincide in equilibrium condition and why do they separate as quasi-Fermi levels in non equilibrium situations?
0
votes
2answers
626 views

Fermi and Boltzmann distribution of carriers in semiconductor

What are the requirements for describing charge carriers (e.g. electrons) in a semiconducting material by - Fermi distribution - Boltzmann distribution When do we apply the one or the other? If the ...
3
votes
4answers
11k views

Working of a p-n junction diode when forward biased

If p-type semiconductor and n-type semiconductor of a diode are equally doped, and if the diode is forward biased, then holes will move toward the n-type semiconductor and electrons will move toward ...
1
vote
1answer
366 views

Electrical conductivity of an intrinsic semiconductor

On which factor does the electrical conductivity of an intrinsic semiconductor depend? It doesn't have an excess of charge carriers in fact, does it?
4
votes
1answer
456 views

Can electrons move through vacuum?

I studied that electronics is the branch of physics which deals with the practical applications of moving electrons through vacuum, semi-conductors and gasses. Can electrons move through vacuum?
3
votes
2answers
247 views

What limits the maximum attainable Fermi Energy for a material experimentally?

Either through doping or gating. What are some good terms to search for if I'm looking for some experimentally obtained values for particular materials? I'm particularly interested in what the limit ...
2
votes
0answers
87 views

Electron Relaxation/Polarization for and n-type Semiconductor

Please help me understand the following (general) statement, referring to electrons in a full valence band of an n-type semiconductor: "An electron filling up the last empty state in the valence band ...
2
votes
0answers
109 views

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.
1
vote
0answers
63 views

1 Mohm Resistivity at cryogenic temperature for doped silicon

I would like to pick the correct doping of silicon to get 1 Mohm cm resistivity at liquid helium temperature of 4.2 K. The metal insulator transition implies that I need a very accurate doping. Are ...
0
votes
2answers
295 views

Carbon in the form of graphite a conductor?

Well, it happens a I have a glucose test strip (One Touch Ultra) which has three electrodes (Counter, Working and Reference) and I'm guessing this electrodes are made from graphite mixed with a ...
1
vote
1answer
101 views

Why is spectral sensivity of a photodiode expressed in A/W

Can someone explain me the meaning of the A/W unit of the photosensivity when reading a spectral response function of the wavelength characteristic of a photodiode?
2
votes
0answers
70 views

Semi-conductors and induced charge

Can a semi-conductor ( germanium or silicon) or a semi-metal ( graphite ) carry an induced charge ?
6
votes
2answers
420 views

Ionized Depletion Region, Why aren't those charged being excited?

Ok so I understand the PN junction, and how when 2 Semiconductor materials are placed together the Electrons will jump into the Holes near the junction creating a Negatively Ionized Atoms on the ...
1
vote
1answer
360 views

Semi-conductor band-gap and deformation potential

Submitting a semi-conductor to stress leads to a deformation in the energy-bands, roughly described by:$$H_{ij} = {\cal{D}}_{ij}^{\alpha\beta}\;\epsilon_{\alpha\beta}$$ $\epsilon$ being the strain ...
0
votes
1answer
190 views

Is it feasible to convert the energy of gamma-photons from gamma-emitting nuclear isomers into electrical power?

It is known that gamma rays emitted by nuclear isomers, naturally occurring or manufactured, carry huge amounts of energy. Co-60 for example decays into the isomeric state of Ni-60 by $\beta ^-$ ...
1
vote
2answers
162 views

How local is the stress tensor?

I am confused by the definition of the stress tensor in a crystal (let's say a semi-conductor), I don't see how it could be "more local" than over an unit cell. I know that in field theory the stress ...
0
votes
1answer
161 views

Carrier Electrons Generation and Recombination Time

When a Electron gets promoted to the conduction band from valence band (In generation) lets say for example in Silicon at room temperature. Is there any way to determine (on average) how long it will ...
1
vote
0answers
56 views

Orientation in GaAs

I can't find the precise definition of what is the orientation of a GaAs lattice. Being the superposition of two fcc lattices (one of Ga, the other of As), I would think that it is the direction of ...
1
vote
2answers
601 views

In the diode equation, why the exponential $\exp$ and the ideality factor $n$ are there? What do they represent & what is their significance?

In the Shockley diode equation, why the exponential $\exp$ and the ideality factor $n$ are there? What do they represent & what is their significance? I have to work on Solar Photovoltaics, and ...
2
votes
2answers
295 views

How can electrons be confined in Quantum dots?

Atoms are in the range of $1$ Angstrom while Quantum dots are in the range of $2$-$10$ nm. In any atom, $99.9$% is unoccupied. So if I have a Quantum dots of size $3$ nm and suppose in my Quantum dot, ...
1
vote
2answers
2k views

Why should the Fermi level of a n-doped semiconductor be below the one of a p-doped?

In a pn-junction, the difference in Fermi level between the p doped and the n doped regions causes the apparition of a built-in electric field at equilibrium. This electric field goes from the n to ...
0
votes
1answer
2k views

PN Junction Depletion Region

So it took me a little bit to understand this, but I want to make sure I have a few things right. First of all, when a Crystal Structure with One side N-Doped, One Side P-Doped are in the same ...
0
votes
1answer
62 views

Regarding “Holes” in bands, and Photons

So from learning Band theory, and PN Junction and such, I've learned that photons are created when "holes" are filled in a band, and this is what can create light (Isn't this how LEDs work?) Anyways, ...
0
votes
1answer
74 views

Exciton energy splitting in indirect semiconductor

Let's take an indirect bulk semiconductor and imagine the exciton that build up at the indirect gap. Since we have a bulk semiconductor we should find three p-like orbitals: $p_x,p_y,p_z$. Would their ...
1
vote
1answer
107 views

Piezoelectricity in GaAs

I am studying the piezoelectricity in Gallium arsenide (GaAs), $[110]$ and $[\bar{1}10]$ oriented. Piezoelectricity is usually described microscopically by a 3 index tensor, $d_{ijk}$ where i,j and k ...
0
votes
2answers
2k views

Band Gap/Energy Bands in Semiconductors?

I think i've finally nailed down the Semiconductor Physics (Well the general part, whats and why's etc, as per my previous question) Anyways there is one small part that confuses me, and thats BAND ...
0
votes
1answer
608 views

Explanation for transistor as amplifier

In transistor as an amplifier, we have NPN transistor (base in the middle and emitter and collector at the sides). The collector has electrons in majority because it is N-type. similarly, holes are in ...
1
vote
1answer
511 views

Resistance of Light Dependent Resistor (LDR)

Is there a mathematical expression relating the resistance of Light Dependent Resistor (LDR) with light intensity?
1
vote
1answer
41 views

Looking for a reference book, or book chapter to learn about piezoelectricity

I'm looking for an introduction to the treatment of piezoelectricity, specially in semiconductors emphasizing the dependence on the orientation of the unit cell and the interactive effects with the ...
1
vote
2answers
265 views

Explanation of NMOS processes

Gate (poly-Si + $SiO_2$) and $p^{-}$ silicon operate as capacitors. But how are voltages and charges applied? In order for inversion to occur, there should be charges formed in poly-Si, right? How ...
2
votes
2answers
2k views

Mobility in semiconductors

Good afternoon everybody. I am reading on a book about semiconductor mobility. I have fully understood the definition, but I also noticed that often one talks about high or low mobility. My question ...
0
votes
1answer
2k views

Capacitance per unit area and CMOS case

In a modern 0.35μm CMOS processor, the gate oxide thickness is around 80Å = 8nm. This gives us a capacitance per unit area of $430nF/cm^2$ I am not getting how one gets this capacitance per unit ...
0
votes
2answers
325 views

The direction of electric field in a diode

Why electric field pointing to left? (The middle area is depletion region.) (This is without any external electrical voltage applied.)
0
votes
5answers
3k views

Current through the reverse biased junction in transistor [closed]

A transistor is a three terminal device. One terminal is called emitter, one collector and in between them is base. Now, during biasing the junction between emitter and base is made forward biased and ...
1
vote
1answer
225 views

Semiconductors and localization of the electrons

When looking at the band diagram of a semi-conductor, direct conclusion of the invariance under discrete translations, for a filled state with an electron, one does know precisely it's momentum, so my ...
2
votes
1answer
117 views

How creation of point defects in semiconductors is affected by strain?

When the effect of the strain on solids is discussed, normally the explanation is the following: increasing stress, first point defects created, then dislocations, then plastic deformation starts, ...
0
votes
1answer
94 views

Charge carrier injection in heterostructures - help with concept definition

I have this report to do on "Charge injection in heterostructures". I have been searching and reading but I still have some trouble with the basics, i.e. defining the concept. As far as I understood ...
0
votes
1answer
3k views

Characteristic of a common emitter transistor [closed]

How is Base emitter junction and collector emitter junction biased? How do we determine the value of potential difference between emitter and collector required to be maintained in order to determine ...
3
votes
1answer
261 views

Semiconductor problem: how much Boron is required to establish a certain amount of charge carrier density

The problem description is as follows: Boron is used to dope 1 kg of germanium (Ge). How much boron (B) is required to establish a charge carrier density of 3.091 x 10^17 / cm^3. One mole of ...