^Electrical mobility

The drift velocity acquired by a charge carrier in a unit electric field is called its electrical mobility and is denoted by μ. i.e. . Mobility of electrons in the VB is less than the mobility of electrons in the CB.

Current in a SC is,            I = [v_e n_e + v_h n_h] e

Conductivity of SC is,      σ = e [n_e μ_e + n_h μ_h],

_σSi = 10^–11 _σCu = 10⁺¹³s_{fused quartz}

Due to very small number density of charge carriers the conductivity of intrinsic SCs is very low & they are of no practical utility.