Photoquenching of hopping conduction in low-temperature-grown molecular-beam-epitaxial GaAs

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.