Semiconductors

Semiconductors, the foundation of the modern electronics including many helpful communicating devices such as radios, TV, cell phones etc is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. The conductivity of semiconductor lies in the range of 103 to 10-8 Siemens per centimeter. The common semiconductors are the crystalline solids which include hydrogenated amorphous silicon and mixtures of arsenic, selenium and tellurium in a variety of proportions.

Silicon is used to create most semiconductors commercially. A pure semiconductor is often called "intrinsic" semiconductor. The added materials in intrinsic semiconductor to make them with desired conducting capacity are called "dopants". For example in crystalline silicon the impurities boron and phosphorous are added as dopants. In semiconductors the electrons can have energies only within certain bands which are generally located between the energy of the ground state. Holes, the electron absence as the charge carrier are the main means of conduction in semiconductor devices. Electron hole pairs are constantly generated from thermal energy as well in the absence of any external energy source. The another property of semiconductor that makes them most useful for constructing electronic devices is that they can be made conductors on different levels by introducing impurities into their crystal lattice, called doping. On the production of semiconductors materials the need of pure semiconductor is extremely high because even small impurity present may effect the labeled conduction of that semiconductor.
Semiconductor being the heart component of microprocessor chips as well as transistor, it have had a monumental impact in our society. The more achievement in production of fast working semiconductors is still desired.