Intrinsic Conduction
If a semiconductor material is cooled until it reaches a temperature of -273 ° C (0 K), the semiconductor material will not be able to conduct electricity, this is due to the absence of free electrons contained by the material. So sushu -273 ° C, the semiconductor material into islator. When a semiconductor material with a temperature of -273 ° C, heated to a temperature of 0 ° C, then the semiconductor material ranging can conduct electric current.
Conductivity type (ρ) semiconductor material rises exponentially (quadratic) to the temperature rise. Why with heating (heating) can make a semiconductor material becomes conductive? When a crystal is heated, the atoms of the crystal will not stay silent, but moving in all directions. As a result, the atomic bonds of the bound electrons (valence electrons) apart, so it turned into a free electron.
The free electrons become more and more, so that the conductivity of materials semikondukor also be increased. Of the phenomenon can be diatakan that the conductivity of semiconductor materials change depending on the temperature.
Extrinsic Conduction
Electronic components such as diodes and transistors made of semiconductor materials. For example diode is made of two types of semiconductor materials P type and N-type
Figure 2.3 The structure of crystalline silicon atom
So that the conductivity of semiconductor materials for electronic components is not temperature dependent (intrinsic conduction) then pursued another way, namely mixing a crystalline another atom to atom crystal semiconductor material. This method is commonly called doping. For example crystalline silicon atom has four valence electrons in the crystal-doping with arsenic atom has five valence electrons, as a result of this mix will be an excess of electrons, and is referred to as N-type semiconductor material
Figure 2.4 N-type semiconductor material
Conversely when crystals of silicon atoms in the crystal -dopping with the indium atom has only three valence electrons, then this mixture will be a shortage of electrons, resulting in a P-type semiconductor material
Figure 2.5 P-type semiconductor material
Electronic components such as diodes, transistors and SCR, made of a combination of P-type semiconductor material and the type N.