Theory of photoconductivity and photoluminescence of amorphous semiconductors at low temperatures

A theory of tunnel radiative recombination of nonequilibrium carriers in an amorphous semiconductor at low temperatures is developed, accounting for energy relaxation and spatial diffusion of carriers via hops between localized states of the band tails. The problem of the fate of a solitary electron-hole pair is solved by calculating the probability, eta(R), that a diffusing electron will move away from the hole over a distance R, avoiding recombination with the hole. A theory of the stationary state of the system is developed using the eta(R) function, and the photoconductivity and photoluminescence of an amorphous semiconductor at low temperatures are calculated.