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.
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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?
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105 views
Does anyone know the difference and relation between $k\cdot p$ method and tight binding (TB) method?
Among the methods of calculating energy bands for crystals, first-principles method is the most accurate. Besides first principles, two commonly used modeling methods are the $k\cdot p$ method and ...
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Is it viable or possible to make your own transistor?
Just wondering if it is possible/viable to construct your own transistor, not small like todays, but the same scale as the one created at Bell Labs.
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how does zener diode maintain potential across its terminals?
My physics book has a topic about zener diodes being used as voltage regulators in the reverse bias.
Well, I'm curious to know how does the zener maintain the potential across its terminals after it ...
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68 views
weight of fully loaded RAM
I had read a post
Is a hard drive heavier when it is full?
It states, there is some difference in the weight of fully loaded hard drive and an empty hard drive due to different orientation of ...
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142 views
Why do the drift and diffusion components cancel for each type of carrier if EHP generation plays such big role in p-n-junctions?
I have always argued to myself that drift and diffusion components of the current though a p-n-junction cancel for each type of carrier because any electron diffusing from n into p will sooner or ...
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115 views
Donors/Acceptors in Metal Oxides
Can anyone explain to me why most articles describe chromium as an acceptor in titanium dioxide? In TiO2, titanium has the charge state Ti$^{4+}$ and oxygen has the charge state O$^{2-}$. When Cr ...
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75 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, ...
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55 views
In solar cells, do photons break apart electron-hole pairs, or create them?
Some sources say that when a photon hits the PV cell, it breaks apart electron-hole pairs. Other sources say that photons create electron-hole pairs. Can anyone explain which one is right? I've read ...
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78 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 ...
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30 views
Are $A$ and $J$ in Black's equation (for electromigration reliability of wires/interconnections) independent?
Black's equation is an empirical model to estimate the MTTF (mean time to failure) of a wire, taking electromigration into consideration. Since then, the formula has been getting popularity in ...
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82 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 ...
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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 ...
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Would HgTe be a topological insulator?
In "Quantum Spin Hall Insulator State in HgTe Quantum Wells", researchers observed a 2D topological insulator by sandwiching HgTe between CdTe. Is the CdTe really necessary? Would Vacuum/HgTe/Vacuum ...
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199 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 ...
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74 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?
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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 ...
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186 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 ...
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Modern and complete references for the $k\cdot p$ method?
I've recently started studying the $k\cdot p$ method for describing electronic bandstructures near the centre of the Brillouin zone and I've been finding it hard to find any pedagogical references on ...
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41 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 ...
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146 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 ...
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3answers
400 views
Indirect band gap semiconductor for LEDs?
Can someone please explain why Indirect band gap semiconductor can not be used for LED creation. Can you also please give me some reference link for details.
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58 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? ...
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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 .
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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 ...
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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 ...
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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 ...
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196 views
Equation for finding electrical resistance
I want to know how the flow of electrons will change when I change the tempertature from 100 F to 250 F in a silicon semi-conductor (ex: computer mouse)
How can I find this out?
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176 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 ...
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64 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 ...
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47 views
fermi level in equilibrium and nonequilibrium situation
Why do the fermi level for electrons and holes coincide in equilibrium condition and why they separate as quasi fermi levels in non equilibrium situation?
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124 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?
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332 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?
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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 ...
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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.
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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 ...
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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 ...
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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?
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Semi-conductors and induced charge
Can a semi-conductor ( germanium or silicon) or a semi-metal ( graphite ) carry an induced charge ?
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475 views
(If and) Why does cold temperature affect semiconductors?
I had a college student build an overclocked PC using phase-change technology. (This is essentially an air-conditioning unit with the evaporator attached directly to the motherboard.) He said that ...
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222 views
Resistance of Light Dependent Resistor (LDR)
Is there a mathematical expression relating the resistance of Light Dependent Resistor (LDR) with light intensity?
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102 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 ...
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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 ...
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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 ...
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218 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 ...
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How can a force be applied on hole? [duplicate]
What is actually a hole? Actually that is not a particle, but books are explaining that in semiconductors the polarity of Hall effect depends on the type of charge carriers whether it is p type or n ...
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60 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 $\beta ^-$ ...
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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 ...
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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 ...
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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 ...
