Questions tagged [semiconductors]
Most generally a class of materials that are neither insulators or conductors in their natural state, but which can be manipulated via doping or electric fields to change their conduction state. Silicon, Germanium, and GaAs are some usual materials. The term is also used to speak about devices that are made from such materials, for example, a processor from Intel can be called a semiconductor.
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A problem from shift in the fermi energy level [closed]
if the effective mass of holes in a semiconductor is 5 times that of the electron, at what temperature would the fermi level shift by 15% from the middle of the forbidden energy band? (given that, eg =...
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Jump on varistor I/V curve when "passing" through max. leakage current region to max. clamping voltage region?
I'm taking a course on semiconductor physics and another on something like "usage of electronic devices". On both I've come across the I/V curve on a varistor, this is:
I cannot find the ...
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Simple circuit to bypass preamp when battery fails
A guitar has an on-board battery powered pre-amp between the pickups and the output jack. This is great until the battery fails, when it goes dead until the battery is replaced.
I would like to have a ...
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Noise in classical quantum transmission
In classical quantum transmission, we introduced a scattering model that includes two components: free projection and collision
Now, in this figure, this model is introduced that when it goes up in ...
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Series connection of diode and resistor. Why is there a constant voltage across the diode?
So I know that a diode can be described using the Shockley equation and after a certain voltage, the diode current begins to increase rapidly. The nominal 0.7 volts. I also know that this voltage ...
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How do you justify energy band bending in an unbiased MOS Capacitor?
Here is a MOS Capacitor:
(Image source: Chapter 5 of Modern Semiconductor Devices for Integrated Circuits by Dr. Chenming Hu)
Now lets consider the idea that the gate voltage is held at 0V, just like ...
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Carrier concentrations versus temperature and doping in Matlab
I am currently self studying structure of semi-conductors and I would like to make a graph in Matlab of the number of carriers as a function of temperature and doping. Let's say that I am testing ...
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Diffusion Current for Non-Linear Charge Carrier Configurations
Diffusion current in a MOSFET device can be calculated using Fick's Law per \$J=-qD\frac{d \rho}{dx}\$. It is often taken that the charge carrier configuration (\$\rho\$) across the MOSFET channel is ...
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Where is the flaw in this transistor, FET, Diode design?
I'm a hobbyist and I've designed and built (fabbed a small circuit board, schematic attached) a circuit to power a brushless DC motor using a solar panel which also charges a stand-by battery and ...
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What is a precise definiton of "cut-in" voltage as applied to diodes?
What is the "cut-in" voltage or knee voltage of a diode or transistor?
In a lot of books I read that the cut-in or knee voltage of a diode (or transistor) is when the diode starts conducting ...
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Semiconductor device testing [closed]
I'm a graduate engineer who's recently started a job testing silicon wafers consisting of both power MOSFETs or diodes and some IGBTs.
Unfortunately there's little in terms of support and training ...
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Electron holes and negatively charged particles [closed]
I'm studying BJTs and have a kind of legacy question. Is there any relation with electron holes and the positive charged point charges you'd see in simple Coulomb law applications?
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How to calculate the diffusion length in modulation doping?
I have read a paper about an application of modulation doping in bulk thermoelectric materials. In this paper, the nanoparticles diffuse carriers into the host materials, and I want to estimate the ...
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Bipolar Junction Transistor operating modes
If I use a BJT transistor as a switch, the transistor operates in the saturation or cut-off region, not in the active region.
However, some sources use the formula IC = β·IB. However, this formula is ...
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Why are microprocessors made using silicon and not germanium? [closed]
I heard that microprocessors are usually made using silicon, yet germanium has a better conductive state.
Why isn't germanium not chosen instead, taking to account that better conductors provide ...
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