We have observed IR photoquenching of the hopping conduction in GaAs samples grown by molecular beam epitaxy at the low temperature of 250 °C and annealed at temperatures from 300 to 600 °C. A key element in the success of this study is removal of the layers from their substrates. The hopping conduction recovers at about 140 K, with a thermal activation energy of about 0.3 eV.
& Look, D. C.
(1992). Photoquenching of Hopping Conduction in Low-Temperature-Grown Molecular-Beam-Epitaxial GaAs. Applied Physics Letters, 61 (12), 1438-1440.