All Questions
Tagged with electricity semiconductor-physics
61
questions
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59
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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 ...
- 21
-1
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1
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41
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Isn't heating insulator enough for sufficient electrons to escape valence band and conduct electricity?
Diamond has about 5.5eV of energy gap, So If I heat diamond it will get atleast 1J energy which is enough to excite about 10^18 electrons, But Diamond still not conduct electricity, Why?
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56
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Current Amplification in Common Base Transistor
How does a common base transistor amplify current if a small part of its emitter current gets divided into base current and the rest goes to collector current? If the input signal is applied to the ...
0
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1
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649
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Why is generation rate equal to recombination rate in extrinsic semicondcutor?
The mass action law states, that the product of electron concentration and hole concentration is equal to the square of the intrinsic carrier density. That applies to both intrinsic and extrinsic ...
1
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1
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213
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How can NO charge carriers exist in the depletion region?
I learned that no charge carriers exist in the depletion region of a PN junction due to the balance between the diffusion current and the drift current due to the electric field created by charged ...
- 471
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71
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How do I calculate the standard uncertainty? Task on determination of energy gap width of semiconductors
I am creating a report for my physics class and all I have left to do is calculate the standard uncertainty for this formula.
$$ \ln \left( \frac{R_{T}}{R_{\infty}} \right) = \ln \left( R_{T} \right) -...
- 111
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49
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Where does the drift current in a pn juntion come from?
I know I know. There are around 4 similar questions on here, but they do not properly answer my question.
I'd like to know where the drift current in a pn juntion (no bias) comes from. From what ...
- 23
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25
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Do you get correct graph of transfer characteristic, if you take +ive Vds(constant) value instead of -ive. As mostly CNTFETs are p-chnl FET
I'm studying transfer characteristic curve of CNTFET to get value for mobility, S.S, etc. According to my basic background knowledge, NMOS curves lie in the 1st quadrant. While for PMOS they lie in ...
- 11
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2
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93
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Can we measure resistance of a diode using Ohm's law $V=IR$ for a specific value of voltage and current?
As a diode doesn't follow $V$ proportional to $I$, I was wondering if we can use Ohm's law to calculate its resistance for a specific set of voltage and current, as its resistance varies as per the ...
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31
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Will there by a voltage drop in the p-type in the diode?
Assume we have a pn diode, and we have forward bias so that we get electricity through the diode.
My question:
Will there be a voltage drop over the p type? (NOT the depletion laywer, but the rest of ...
- 199
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3
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985
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When an electron moves in the valence band, does it need energy?
I am wondering what actually happens when an electron moves in the valence band. As I understand an electron needs energy to free itself from an atom. Is it so that the electron gets energy to free ...
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3
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1
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720
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Why do electron holes move away from heat?
I'm currently learning about thermoelectric generators and I learned about the two p and n semiconductors. I understand how the n-type semiconductors works which is that when one side gets heated then ...
- 329
6
votes
4
answers
447
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PN junction: not sure to understand why reverse-biais lead to negligible current
My question is very highly related to Why doesn't current flow in reverse biased diode?
Basically, I would like to understand in more depth John Rennie answer. At $t=0$, I consider a PN junction ...
- 1,450
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729
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What is the relation between the short-circuit current and the band gap energy in solar cells?
For the VOC it is:
VOC = E_g - something,
where something is positive and depends on the Urbach energy. Otherwise it should be linear:
https://aip.scitation.org/doi/pdf/10.1063/1.49397
For the ISC I ...
2
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1
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78
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Why don’t illuminated series connected (photo-)diodes bias each other?
When you connect, let's say, three photodiodes or solar cells, with a load, and you measure the voltage across the middle photodiode. Will the voltage change if
the adjacent cells are in the dark
if ...