All Questions
Tagged with electricity semiconductor-physics
61
questions
2
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23k
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Why in a conductor increase in temperature makes the atoms vibrate but in a semiconductor the kinetic energy of the free electrons is increased?
When temperature is increased in case of a semiconductor the free electron gets more energy to cross the energy gap to the conduction band from the valence band.so now more electrons can go easily to ...
- 31
0
votes
3
answers
252
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Doubt in working of p-type semiconductors
Correct me if I'm wrong, but as far as I know, in p-type semiconductors, first the excitation of an electron takes place from the valence band to the conduction band due to thermal energy, then this ...
- 426
0
votes
1
answer
75
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Point resistance
The resistance of a given object is expressed through:
$$R=\rho\frac{l}{A}$$
I'm wondering if there is any quantity like resistance at a specific point. For example, $R$ for a copper wire with l=...
- 3
1
vote
2
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954
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Does an electron physically flow? [duplicate]
In a DC current in a conductive wire, is it more accurate to think of one electron wiggling its way through a sea of electrons... or to think of one electron bumping into another, which bumps into ...
- 445
2
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2
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3k
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Construction of Peltier tiles
I'm learning about the construction of Peltier tiles from Wikpedia. However, some of the statements in the article are not at all clear.
Here's the extract:
Two unique semiconductors, one n-type ...
user139621
1
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0
answers
1k
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Differences in conductivity as temp rises for intrinsic vs extrinsic semiconductrs
For a doped semiconductor, near the end of the extrinsic temp region due to heightened effects of lattice scattering conductivity goes down "temporarily" (temperature wise).
What happens to the ...
- 11
1
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3
answers
6k
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Are thermistors and filament bulbs ohmic?
Conductors are ohmic if they have a constant resistance given that the physical conditions, such as temperature, are constant.
A filament bulb and thermistor are considered to be non-ohmic because ...
- 1,307
0
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2
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3k
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Why does current have to flow in the same direction?
If current is just the movement of charged particles, why do the all have to move in the same direction?
For example, if you reverse-bias a diode (connect the positive terminal to the n-type side ...
- 165
1
vote
1
answer
66
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How can I create an ohmic contact with selenium?
I would like to be able to measure the electrical resistance of selenium past its melting point, but to do this I need to create an Ohmic contact between the selenium and my multi-meter. What metals ...
- 127
0
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0
answers
37
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How am I obtaining silicon with resistivity proportional to the number of conduction electrons?
The resistivity of silicon is given by
$$\large\rho=\rho_0e^{\Large{{\frac{E_g}{2k_BT}}}}$$
and the number of conduction electrons in a semiconductor conduction band is
$$\large n_{\text{...
- 4,607
0
votes
1
answer
180
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If we inject charge carriers into insulators, will they become conductors?
Since there're also valance band and empty band in insulators, if we introduce electrons in empty band or holes in valance band, will it conduct electric current like semiconductors?
For example, we ...
- 383
2
votes
0
answers
177
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Van der pauw method for an isolated hole
Van der pauw method is a way to measure the resistivity of a material with arbitrary shape while it meets some specifications ( being homogeneous and ...).
One of the conditions is that the sample ...
- 322
1
vote
1
answer
216
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Simulate Band Bending and Band Alignment in Semiconductors
Are there softwares (simple ones preferred) where we can simulate the band alignments and band bending of a p-n junction, where we can vary properties of the junction materials such as carrier ...
0
votes
1
answer
502
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Quasi-fermi levels in a solar cell?
I was wondering, if my fermi levels splits up due to n and p type doping into two fermi levels, one for the p type one for the n type, and now due to light radiation my fermi levels split up into 2 ...
user85397
3
votes
1
answer
3k
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Do batteries provide electrons
In chemistry, the reaction at negative electrode produces electrons,which flow to the positive electrode through the circuit. But then, if circuit has a conductor, then wouldn't it also release ...
- 41
-1
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1
answer
183
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How does the solar cell work?
I know that a solar cell consists of a transistor (NP). First step it creates a barrier between the n type and the p type junction. Then the sunlight (i.e, the photons) supply energy to the electrons ...
- 21
1
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4
answers
16k
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How is current produced in semiconductors or metals?
I think current is the movement of electrons through the wire or semiconductor, thus when I press the switch of the light bulb the electrons go from positive part to tungsten and light is produced. ...
- 11
1
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1
answer
1k
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Question on Shockley's equation for FETs
I'm currently studying FETs (Field Effect Transistors) in Navy school. What I know so far is that in FETs, $V_{gs}$ is reversed biased, creating a depletion zone. What this means in plain English is ...
- 121
2
votes
1
answer
718
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How to check the ohmic contact to the film?
I have a thin semiconductor film deposited on an isolating substrate. I would like to check different metals to find out do they form the ohmic contact or Schottky barrier.
What is the best way to do ...
- 21
1
vote
0
answers
84
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How does Passivation in Mercury-arc-valve cause "diode" behavior
Does passivation of lead anodes cause them to become semiconductors?
Or even become diodes (eg. a p-n passage)?
How does this work on an atomar level?
This question has been risen by trying to ...
- 243
3
votes
1
answer
11k
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How does temperature affect an electrical current
Synopsis
I have read an interesting article J. Halderman et al. "Lest we remember: cold boot attacks on encryption keys" in computer science regarding cold booting.
The paper discusses how the use ...
- 133
1
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2
answers
2k
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What actually happens at the microscopic level in a Zener diode in reverse bias?
A Zener diode is used as a voltage stabilizer. The graph of current vs voltage of Zener diode clearly shows that there is a constant voltage across Zener after the breakdown voltage as the current ...
- 3,905
5
votes
3
answers
537
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What can justify the decrease of the electrical conductivity with the increase of light intensity?
I have currently been working with a sample that "appears to" decrease its resistance when I cover it and protect it from light.
Basically it presents the opposite behaviour of a photoresistor.
What ...
- 1,334
0
votes
2
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159
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Need an intermediate resistivity part/material
I need a part or material for a planned experiment (the experiment is similar to those described in my articles http://arxiv.org/abs/1208.0066 and http://arxiv.org/abs/1109.1626 ). The problem is that ...
- 27.1k
2
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3
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2k
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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 .
- 29
5
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2
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29k
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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 ...
- 59
8
votes
2
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1k
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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 P-...
user20118
0
votes
1
answer
609
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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 ...
user20118
3
votes
1
answer
335
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Theory of Space Charge in a Planar Diode
A planar diode in a vacuum bulb can support current in only one direction. To even get current flowing, you have to heat up the cathode filament to excite the electrons. However, once current is ...
- 143
2
votes
1
answer
3k
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How is contact resistivity defined for a Schottky contact, or the Schottky barrier height for an ohmic contact?
Based on the transfer length method (TLM), one can accurately calculate the contact resistivity for an ohmic contact, by evaluating the absolute resistance measured through the test structure and ...
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