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Semiconductor

A semiconductor is a material which has electrical conductivity between that of a metal and an insulator. Semiconductors have a number of unique properties. They can change the conductivity by the addition of impurities (doping) or by the application of electric fields or light. This ability makes semiconductors very useful for devices that amplify, switch or convert electrical energy. The study of semiconductors and their properties relies on quantum physics to explain the motion of electrons inside a lattice of atoms.

Semiconductors are the foundation of modern solid state electronics. This includes radios, computers and telephones. Semiconductor-based electronic components include transistors, solar cells, light-emitting diodes and digital and analog integrated circuits. The increase in understanding of semiconductor materials has allowed the continuing increase in the complexity and speed of semiconductor devices.

A pure semiconductor is a poor electrical conductor as a consequence of having just the right number of electrons to completely fill its valence bonds. Through different techniques, the semiconductor can be modified to have excess of electrons or a deficiency of electrons. In both cases the semiconductor will become more conductive.

When the semiconductors are doped they join to metals, different semiconductors, and to the same semiconductor with different doping. The result of this junction often strips the electron excess or deficiency out from the semiconductor near the junction. The depletion region is rectifying and used to further shape electrical currents in semiconductor devices.

Electrons can be excited across the energy band gap of a semiconductor by various methods. These electrons carry their excess energy over a distance before dissipating their energy into heat. This effect is essential to the operation of bipolar junction transistors.

Electrons in semiconductors will absorb light and retain the energy from the light for a long enough time to be useful for producing electrical work instead of heat. This effect is used in the photovoltaic cell. Semiconductors can use thermoelectric generators to convert temperature differences into electrical power and vice versa. Peltier coolers use semiconductors for this reason.

Analysis of unbiased PN junction and physics

see attachment please please, please, please I need help to solve this Q I solved parts a,b, and c still need help in other parts the reference book I am using ( the physics of solar cell (nelson) ) Ch6 Here is some website can help http://ecee.colorado.edu/~bart/book/book/chapter4/ch4_3.htm http://my.ece.msstat

Estimate of power output of crystalline Si Boule photovoltaic

You have a 150 mm diameter boule of Si that is 1 meter long. What is the electrical power output you might expect to achieve if this material were made into solar cells - explain all assumptions. Most silicon monocrystals are grown by the Czochralski process into ingots of up to 2 meters in length and weighing several hundred

Plot of the Fermi distribution function for different temperatures

plot the fermi distribution function at 200,300 and 400k(all on grah) and discuss the results in comparison to question 4. http://lyle.smu.edu/ee/smuphotonics/Gain/CoursePresentationFall03/CarrierConcentration_0822.pdf http://ecee.colorado.edu/~bart/book/distrib.htm (2.4.3) these webs may help to plot the Fermi Function

Physics: Batteries, Resistance and Current; Resistance in a Wire

Batteries, Resistance and Current Prelab: 1. What is the resistivity () of a resistor? What characteristics of a resistor affect the resistivity? Write a formula for this relationship, label each variable and indicate the units used to measure each. Would resistivity be constant for a specific resistor? 2.

Current Electricity: A rod with variable resistivity.

The resistivity of a semiconductor can be modified by adding different amounts of impurities. A rod of semiconducting material of length L and cross-sectional area A lies along the x-axis between x=0 and x=L. The material obeys Ohm's law, and its resistivity varies along the rod according to p(x)= p0exp(-x/L). The end of the rod

Non-Ohmic Device: Algebra-based physics

Please give an example of a non-ohmic device BESIDES A LIGHT BULB. Explain what this non-ohmic device is. Explain what makes this non-ohmic device work. Explain why it is non-ohmic. Please list something you found interesting about the non-ohmic device you picked. Also, please list one question you have about the non-

Semiconductor Light Detectors

A p-n photodiode acts as a photocell, the circuit is shown in this document. Outline the band profile of the diode for infinitely large RL for different levels of illumination.

Flatband and threshold voltages

An Al-silicon dioxide-silicon MOS capacitor has an oxide thickness of 450Angstroms and a doping of Na=10^15 cm^-3. The oxide charge density is Q'ss=3x10^11cm^-2. Calculate (a) the flat-band voltage and (b) the threshold voltage. Sketch the electric field through the structure at the onset of inversion.