INFRARED MEASUREMENTS IN ANNEALED MOLECULAR-BEAM EPITAXY GAAS GROWN AT LOW-TEMPERATURE

We have utilized an infrared absorption technique to study deep level defects in molecular beam epitaxy GaAs grown at 250°C. From an observed broad absorption band below the conduction edge, the concentration of defects is estimated to be ≈5×1019cm-3 in an as-grown sample. The concentration of defects decreases exponentially by one order of magnitude due to annealing of the sample at temperatures of 400-500°C. From the temperature dependence of the defect concentration, the migration energy of defects is calculated to be 0.52±0.02 eV. The measured migration energy shows that part of the defects are arsenic interstitials.© 1995 American Institute of Physics.