Local order of Te impurity atoms and free electron concentration in heavily doped GaAs : Te

Zn this paper we briefly show the results of joined studies of the free ele ctron concentration and X-ray diffuse scattering (detected by HR XRD - reci procal space maps) as a function of Te atoms concentration in GaAs and cont rolled annealing of samples at high temperatures 700-1200 degrees C. The fr ee electron concentration can be reversible changed between low and high va lues merely by a proper annealing of GaAs samples with Te concentration hig her than similar to 4 x 10(18) cm(-3). Strong X-ray diffuse scattering is o bserved in annealed samples, if electron concentration is lowered. Detailed features of X-ray scattering in the reciprocal space can be very well unde rstood within Krivoglaz microscopic model of scattering due to local correl ations of impurity positions in a solid solution (local order) and related crystal lattice distortions. (C) 2000 Elsevier Science S.A. All rights rese rved.