RADIATIVE RECOMBINATION AND IMPURITY-DEFECT INTERACTIONS IN NUCLEAR-DOPED GALLIUM-ARSENIDE PRODUCED UNDER DIFFERENT IRRADIATION AND CRYSTAL-GROWTH CONDITIONS

A. study is made of the low temperature (T=4.2 K) photoluminescence of nuclear-doped, Czochralski grown (HP and LP LEC) GaAs crystals irradi ated by a flux Phi=5X10(17) cm(-2) of thermal neutrons with a flux rat io of thermal and fast neutrons in the range from 10-200, In the initi al stages of annealing of irradiated crystals to T < 600 degrees C, th e main feature in the luminescence spectra is a band involving transmu tation germanium accepters. Residual carbon accepters in the irradiate d crystals interact with radiation defects and form nonradiative recom bination centers. Decay of these centers and stabilization of the inte nsities of the edge and impurity (involving carbon accepters) recombin ation radiation bands are observed in the final stage of annealing at T=600-700 degrees C. The experimental variations in the edge and impur ity (involving residual, C, and transmutation, Ge, accepters) bands du ring annealing are analyzed using models for the localization of trans mutation impurities and impurity-defect interactions in irradiated cry stals. (C) 1996 American Institute of Physics.