The intrinsic carrier density, also known as the intrinsic concentration, is the number of charge carriers (electrons or holes) per unit volume in a pure semiconductor material at thermal equilibrium, i.e. when no external voltage is applied.
The intrinsic carrier density can be calculated using the band gap energy, effective mass of electrons and holes, and temperature. It can be expressed mathematically as ni = Nc * Nv * exp(-Eg/2kT), where ni is the intrinsic carrier density, Nc is the effective density of states in the conduction band, Nv is the effective density of states in the valence band, Eg is the band gap energy, k is the Boltzmann constant, and T is the temperature in Kelvin.
The intrinsic carrier density is affected by temperature, band gap energy, and the effective masses of electrons and holes. It is also dependent on the type of semiconductor material, as different materials have different values for their intrinsic carrier density.
The intrinsic carrier density is an important parameter in determining the electrical properties of a semiconductor material. It helps in understanding the conductivity, resistivity, and other characteristics of the material. It is also used in the design and fabrication of electronic devices such as transistors and diodes.
The intrinsic carrier density is the number of charge carriers in a pure semiconductor material, while the extrinsic carrier density includes both the intrinsic carrier density and the additional charge carriers introduced by doping the material with impurities. The extrinsic carrier density can be controlled by the amount and type of dopants, whereas the intrinsic carrier density is an inherent property of the material.