An infra-red absorption technique was used to study deep-level defects in molecular beam epitaxial samples which had been grown at 250C. On the basis of a broad absorption band which was observed below the conduction edge, the defect concentration was estimated to be about 5 x 1019/cm3 in as-grown samples. The defect concentration decreased exponentially by an order of magnitude upon annealing the sample at temperatures of between 400 and 500C. From the temperature dependence of the defect concentration, the defect migration energy was calculated to be 0.52eV. The measured migration energy showed that some of the defects were As interstitials.

Infrared Measurements in Annealed Molecular Beam Epitaxy GaAs Grown at Low Temperature. N.Hozhabri, S.H.Lee, K.Alavi: Applied Physics Letters, 1995, 66[19], 2546-8