All Questions
Tagged with semiconductors solid-state-devices
62
questions
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412
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Derivation of microscopic Ohm's law from macroscopic version?
What I tried was:
$$\overrightarrow{E}= - \triangledown V \qquad \qquad\qquad\qquad (1) $$
$$V= IR\qquad \qquad\qquad\qquad\text{(Ohm's law for materials where V}\propto \text{I)}$$
$$\text{...
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1
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800
views
Given a energy band diagram, can you always calculate potential, electric field, and charge distribution?
Given a band diagram, where do you start to get the electric field and charge distribution?
- 447
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1
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737
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Electric field of Schottky diode
Reference: Device Electronics for Integrated Circuits 3rd Ed. Richard Muller
I am trying to understand how to calculate the maximum electric field. The answer given in the book is $$E_{max} = \frac{-q ...
- 447
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1
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658
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Why does the value of shunt resistor need to be very high for solar cell's greater efficiency?
In the circuit equivalent of a solar cell, shunt resistor is described as "The irregular polycrystalline lattice grain boundaries that resist to the flow of electrical current in the silicon ...
1
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1
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3k
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Why does channel length modulation only occur in the saturation region?
As drain voltage is increased, the reverse bias across the drain-body junction also increases and thus the width of the junction should also increase which should deplete the channel length as well. ...
- 469
2
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1
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474
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Is saturation region defined for a "given" collector emitter voltage?
I have seen the traditonal saturation regions graphs (attached). The graph gives the impression that there is a huge region which is saturation region. Shouln't the saturation region be for a "...
- 271
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3
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1k
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Does the collector voltage have to be greater than the emitter voltage by few tenths of a volt for an NPN transitor
For an NPN transistor, does the collector voltage have to be greater than the emitter voltage by few tenths of a volt for it to be in active state? If yes what is the reason?
Also it says greater by a ...
- 271
2
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57
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How does the stored charge gets decayed when going from forward bias to zero bias?
In a pn junction diode when forward biased, excess electrons and holes get stored in p and n regions respectively.
If we short the diode by connecting p,n terminals with a wire,
how do these stored ...
- 1,150
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2
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843
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Relation between forward bias and current in a diode
I have seen the VI graph to depict the relationship between forward bias and current. (left graph) and I think I get it. I have also seen another graph (right graph) to depict the relation between ...
- 271
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2
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1k
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How can a Zener diode maintain a constant voltage?
A Zener diode in reverse bias more than breakdown starts conducting. If you increase the reverse bias:
It conducts more i.e current in it increases
The voltage across it remains same
I think I get ...
- 271
2
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1
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993
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What is the exact meaning of 0.7V voltage drop in a forward-biased diode?
this question is partially (but not totally) discussed here:
Why do diodes have a voltage drop?
Does the power drop on a diode become entirely heat?
The conclusion is that, in a forward-biased diode ...
- 3,550
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72
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How to convert spontaneous emission into stimulated?
I have a semiconductor diode that has spontaneous emission (LED).
The question is what can I change in the fabrication of the diode to improve its performance such that the diode gains a stimulated ...
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0
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61
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MOSFET current at very low temperature (4K)
I am trying to model the current at low T. To do so I need to compute the integral between the fermid diract statistic and the conductivity, with respect to energy. My problem is that I cannot ...
- 1
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46
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What is the structure of GaAs?
Ga has three valence electron, and As has five valence electron. How do they share electrons so that each has 8 valence electrons? Does each Ga atom share 5 electrons with 5 different As atoms?
- 447
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1
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374
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Does hole concentration fall below the intrinsic concentration, if Si is doped with pentavalent impurities?
If we increase N type doping in a pure Silicon then according to the equation
$$P_n=\frac{n_i^2}{N_D}\text.$$
Then mathematically, hole concentration is less than \$n_i\$, if \$N_D>n_i\$.
Why does ...
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