The temporal evolution of EL2 thermal recovery was investigated in detail by using a piezoelectric photo-thermal method. The results revealed a simple saturation behavior above 120K, and a sigmoid-like behavior below 120K. Both were quantitatively analyzed using an autocatalytic-reaction rate equation. The latter recovery mode indicated a correlation between defects, for which recovery promotion via charge transfer from recovered to unrecovered EL2 defects could be proposed. A 3-center complex model (VAs-AsGa-GaAs) was proposed for the microstructure of EL2.

Inter-Defect Correlation During Thermal Recovery of EL2 in Semi-Insulating GaAs - Proposal of a Three-Center-Complex Model. A.Fukuyama, T.Ikari, Y.Akashi, M.Suemitsu: Physical Review B, 2003, 67[11], 113202 (4pp)