STUDY OF NONLINEAR EXTRINSIC LUMINESCENCE IN GAAS .2. ROLE OF AUGER RECOMBINATION

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. Copyright © 1979 WILEY‐VCH Verlag GmbH & Co. KGaA