All Questions
Tagged with semiconductor-physics quantum-mechanics
173
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Graphene dispersion at Dirac points
After deriving the dispersion relation of graphene:
$$ E(k) = \pm t \sqrt{3+2\cos{(k_y \sqrt{3} a)} + 4\cos{\bigg(\frac{3a}{2} k_x \bigg)} \cos{ \bigg(\frac{\sqrt{3}}{2}a k_y \bigg)} } $$
how do I see ...
- 101
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50
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Why would a depletion "layer" form in a PN junction?
I understand that electrons diffuse from the N to the P region due to the concentration difference. This diffusion of electrons creates an electric field opposing further diffusion.
What I don't ...
1
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1
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Where can I read about excitons?
I'm having a tough time finding a good reference for excitons. I know next to nothing about them, and I'd like to find a good book/paper/notes that would introduce it in a slow, pedagogical way. ...
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Current Inside the Depletion Region Forward Biased PN Junction
For a forward biased PN junction, we assume the hole and electron currents are constant inside the depletion region when there is no generation or recombination in the depletion region (shown from the ...
- 63
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34
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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 ...
- 63
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21
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Change in internal chemical potential of electrons in the 2DEG
I was reading about quantum capacitance and came across the following formula:
$$\Delta \mu = \frac{N}{\rho}$$ where N is the number of electrons moved from the metal to the low-density-of-states ...
- 493
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103
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Interpretation of velocity in the de Broglie wavelength of an electron in a crystal
The de Broglie wavelength of a free electron is $\lambda = h/mv$ whre m is the free electron mass, and v is the velocity. Often in introductory solid state physics literature (review articles, lower-...
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84
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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 ...
- 113
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1
answer
39
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Extension from Excitons to Trions
I am curious about the fundamentals of how a trion state is defined. An exciton state is considered a bound electron-hole pair. This can be formed by is we have a ground state which consists of a full ...
- 155
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41
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Basics regarding $k$-space axis and Energy graph in direct semiconductor
We can see from the graphic axes, that energy increases along the y-axis, and k space increases along the y-axis. Considering a direct or indirect semiconductor whichever it doesn't matter, but why ...
- 3
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44
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Wavefunctions of quantum point contacts
I have a question about the potential and wave functions of discrete energy levels of quantum point contacts. Assuming one has a rectengular potential well:
Can the potential of the QPC be assumed to ...
- 45
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102
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Question about k.p Method
I am reading David Miller's quantum mechanics, and I do not understand the derivation for k.p method:
We are particularly interested in the behavior of semiconductors near to maxima and minima.
...
- 123
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1
answer
83
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Zener diode reverse bias I(V) equation
What is the equation for the reverse bias current in terms of voltage applied? And this even be analytically derived? If so, how to derive it.
I can't seem to find good resources on this topic.
- 513
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2
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69
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Physically, up to what size is it possible to miniaturize the process node of a silicon chip? [closed]
With current technology we have managed to manufacture silicon chips of up to 3 nm for the semiconductor industry. To what size is it physically possible to make smaller the process node for these ...
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How can modern transistors have width of only a few dozen atoms?
We typically analyze transistor's work based on a work of a simple pn-junction diode, with some modifications if needed, as it is basically a particular configuration of pn-junctions. We assume the ...
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