The correlation of reverse contrast absorption imaging with photoquenchable deep acceptor centres in semi-insulating LEC GaAs

Reverse Contrast imaging is a photo-quenchable, absorption imaging technique, thought to result from absorption by very deep acceptors with an ionisation energy of approximately E/sub g/ - 65 meV near 4K. At temperatures above 140K, all optical behaviour disappears. In this paper we present Hall data on lightly n-type GaAs both before and after photoquenching of these defects and demonstrate that the predicted acceptor level exists and the concentration of the levels correlates with the RC absorption. Optical cross-sections for this absorption at 830 nm are thus derived.