Semiconductor devices belong to categories of electronic components which are named semiconductors. Clean or unalloyed semiconductor usually not used in these devices, but originally alloyed by admixtures in a semiconductor crystalline grate they become admixture semiconductors.
Admixture semiconductors are alloyed so that to provide surplus of electrons (semiconductors of n - type) or their defect (semiconductors of p - type). The presence of admixtures in a semiconductor crystalline grate is determined by the degree of to conductivity grate.
The single layers of п- or р- semiconductors do not find application, and semiconductor material becomes a semiconductor device only then, when two or more than layers of different types contact with each other. The simplest р- n - transition forms a straightening device or diode. Volt-ampere description of diode is set according to correlation, known as equalization of Shokli or equalization of ideal diode, namely:
I = Io [exp(qV/kT) - 1]
Where Iо is a current of satiation (or current of loss); q is a charge of electron; V is the tension put to the diode; k - Boltzmann; Т is a temperature, К.
Any change of measurand, which causes the change of the expression given above, maybe, certainly, is used for the change of current, flowing through a transition. For example, a diode is sometimes used as a transformer of temperature, as a current of loss of semiconductor changes in the function of temperature. The current of loss of silicon makes approximately 25 nА at a temperature 25 °With and increases to 6.5 мА at a temperature 150°С.