Fine structure of the oxygen-related local mode at 714 cm−1 in GaAs

Abstract

Infrared absorption measurements on a new third state of the Ga‐O‐Ga center in GaAs are reported. This state gives rise to a local mode at 714 cm⁻¹, B’, which is shifted from the band B to lower energy by 0.67 cm⁻¹. The B’ state acts as an intermediate state for the photoinduced conversion from the 730 cm⁻¹ band, A, to B. The kinetics is quantitatively described by a model considering successive capture of conduction‐band electrons, which have been photoexcited from the EL2 level. The reappearance of the band A after quenching of EL2 occurs through the corresponding sequence B→B’→A. The experimental results favor the interpretation of B’ in terms of a third charge state being not accessible at thermal equilibrium conditions.