All Questions
Tagged with semiconductor-physics electronic-band-theory
279
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Why do dopant levels lie in the energy band gap of semiconductor?
Dopants create impurity levels in the band gap, this is what we were taught in semiconductor classes. And indeed that's what's seen in experiments (for example https://www.globalsino.com/EM/page2777....
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How do solar cells really work?
When I read articles on the workings of photovoltaics, the explanation tends to revolve around the idea of PN-junctions, and how an electric field separates charges (electrons and holes). In a Quora ...
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Why do we need to consider interaction for doping atom?
In semiconductors, the intrinsic carrier concentration is calculated by Fermi-Dirac distribution, but for the situation of doping, we need to consider the Coulomb interaction for doping atom, and the ...
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C$_{60}$ fullerene electronic structure, C$_{60}$ insulator
I read a post on Chemistry stackexchange, how to explain that C$_{60}$ is an insulator. The common ground seemed to be that -- in contrast to graphene -- a C$_{60}$ solid consists of separate ...
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Intrinsic band gap vs work function of doped semiconductors
I'm confused about this question on doped semiconductors:
Question: Photoelectrons with a maximum energy of $\ 0.5$ eV are observed when light of wavelength
$500$ nm is incident on a heavily n-doped ...
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Built-In Potential (Forward vs Thermal Equilibruim)
According to my book the built-in potential $V_{bi}$ for a PN junction under thermal equiliubrium is:
$$V_{bi}= \frac{KT}{q}In(\frac{n_{no}p_{po}}{{n_{i}}^2})$$
where $n_{no}$ and $p_{po}$ are the ...
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How to determine the effective mass for multivariate dispersion relation? [duplicate]
Consider the 1D dispersion obtained by the tight-binding method:
$
E(k)=\epsilon_0-t\cos(ka)
$
$\epsilon_0$ is the on-site energy and $t$ is the hopping energy. To find the effective mass, you can ...
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Valence band in silicon (semiconductors)
I recently learnt that in a solid lattice there are many energy levels which are so continuous that they look like bands...
In silicon' valence band,there are those millions of 3p energy levels with 2 ...
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For intrinsic semiconductors, is the gap Energy equals $E_c-E_v$ or $E_c+E_v$?
So I have a problem with the intrinsic Fermi Level because by definition it is in the middle of the gap energy, and knowing that Eg=(Ec-Ev), we should have Ei=(Ec-Ev)/2.
But when we follow the ...
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Can a DC voltage excite a pure semiconductor (or insulator) from the valence band to the conduction band?
I have a question I am sticking around and can't find a satisfying answer. Say I have an intrinsic semidonductor at zero Kelvin (no electrons in conduction band). I apply a DC voltage across it. Can ...
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Bloch functions and covalent bonds in some semiconductors
In a Group IV semiconductor (like Si, Ge), one atom makes 4 covalent bonds with its neighboring atoms. They create in this way the so-called a tetrahedral bond (that of the diamond structure). Each 2 ...
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If an atom loses electron, it becomes a cation; it does not form a hole. However, when electron is lost from a bond, it forms a hole and not a cation
If an atom loses an electron, it becomes a cation, and when an electron is lost from a bond, it forms a hole. This is what the professor told the class, but I am not able to find the reason for that ...
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Where can I read about Valleytronics?
Where can I read about Valleytronics? Are there any good books or review papers on this topic? And which are the most influential papers?
The question was also posted at the Matter Modeling site.
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What determines the energy spacing of individual orbitals within an energy band in a material?
Within a material, electrons exist within energy bands, often referred to as the "conduction" band and the "valence" band (and I imagine there can be other named bands as well). I ...
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Polaron vs Electron energy level
i just started my study in organic semiconductor. I realized to increase conductivity, polarons are formed in the polymer backbone. From what i read due to localised energy state level by polaron that ...
