semiconductor?

Question

1. what is semiconductors

2. why metals are good conductors of electricity while semiconductors have relatively poor conductivity?

3.why plastic deformation(eg. cold rolling) and alloying (eg. in stainless steel) affect the electrical resistivity of metals?

4. what is the difference between intrinsic and extrinsic semiconductor?

5.what is the role of doping in the electrical conductivity of semiconductors

6.what's the difference between n-type and p-type semiconductor?

7.what cause the different resistivity values of metals?

8.why semiconductor possess different electrical resistivity?what is the most dominating factor?

Answer 1

semiconductor is a material with electrical conductivity that is intermediate between that of an insulator and a conductor. The conductivity and other electrical properties of semiconductors are determined by the material's electronic band structure. Semiconductors' electrical properties may be modified by introducing impurities in a process known as doping. The ability to control conductivity in small and well-defined regions of semiconductor material has led to the development of a broad array of semiconductor devices, and these are combined with the simpler passive components to produce a variety of electronic devices.

for all answers to your questions see the site http://en.wikipedia.org/wiki/Semiconductor

Answer 2

It all has to do with how easily electrons can move from one atom to the next in the material. In conductors, electrons are free to jump from one atom th the next, so any voltage applied to the material will cause electrons to flow. The electrons in a semiconductor are free to move once they overcome an energy threshhold (the band gap) in their atom. Specially engineered semiconductor materials are used in electronic devices (also called semiconductors). By joining different semiconductor materials, you can create junctions that only allow current flow in one direction (a diode) or let you control the flow by applying a small voltage (a transistor). This is a gross simplification, of course. Insulators are just materials where the electrons are tightly bound to their atoms and can't be induced to wander.

Answer 3

A semi conductor is a metrial with is not conductor (such as silicon) which is "polluted" with impurities that are conductors. I am afraid that's as far as I can help. (I was just reading an article about semi-conductors on Friday).

Answer 4

I refer you to some good library in your area and read all the good books you can.