Study of non-linear extrinsic luminescence in GaAs. II. The role of auger recombination

Abstract

The excitation intensity dependence of the 0.99, 1.03, 1.2, and 1.3 eV extrinsic emission in heavily doped n-type GaAs crystals (n0 = 5 × 1017 to 2 × 1018 cm−3) is studied at 77 to 300 K. An analysis is given in which a functional intensity dependence of the extrinsic emission on a rate of simultaneous radiative and non-radiative electronic transitions in radiative centres is considered. Linear and superlinear 0.99, 1.03, 1.2, and 1.3 eV extrinsic emission is observed at low temperatures depending on the strength of non-radiative electronic transitions in radiative centres studied. The main features of non-linear extrinsic emission (superlinear emission increase with excitation intensity, a shift of emission quenching curves to lower temperatures as excitation intensity is increased, a change from the superlinear to a linear excitation dependence of emission intensity as temperature is raised) are satisfactorily explained by a model which includes strong non-linear, in intensity, dependence, radiationless transitions in radiative centres. The model discussed takes into account a decrease in the rate of non-radiative electronic transitions in radiative centres as the exciting light considerably changes the electron occupancy of defects associated with the centres studied; as a result the internal quantum efficiency and emission decay time for the luminescence bands are increased as excitation intensity is raised. [Russian text Ignored]