Field Control of the Quantum Efficiency of Radiative Recombination in Semiconductors

The bending of the energy bands in a semiconductor by means of a field effect can be used to: (1) reduce the surface recombination velocity, (2) increase the free-carrier concentration in the vicinity of the surface, and (3) reduce the rate of nonradiative recombination through impurity centers. Under suitable conditions which are described, all these factors combine to enhance the quantum efficiency for radiative recombination within the surface-barrier region. A similar situation prevails in the vicinity of a $p-n$ junction. The effect of a transverse electric field on the radiative quantum efficiency in Ge, Si, and GaAs is described.