Changes in the optical-absorption spectra of transmutation-doped GaAs as aresult of annealing

The optical-absorption spectra of GaAs irradiated with pile neutrons (with integrated fluxes of up to D = 2 x 10(19) cm(-2)) at temperatures of 70, 35 0-390, and 850 degreesC were studied after subsequent isochronous annealing at temperatures as high as 1100 degreesC. It is shown that the free charge carriers with a concentration of n greater than or similar to 10(17) cm(-3 ) appear after an annealing at temperatures of about 400-550 degreesC. The quality of transmutation-doped material was assessed in relation to the con ditions of irradiation and the temperature of the subsequent thermal anneal ing. (C) 2001 MAIK "Nauka/Interperiodica".