Ga Self-Diffusion in GaAs Isotope Heterostructures

Isotopically controlled GaAs heterostructures have been used to study Ga self-diffusion with secondary-ion mass spectroscopy. This approach probes a close to ideal random walk problem, free from perturbations such as electric fields, mechanical stresses, or chemical potentials. The Ga self-diffusion coefficient in intrinsic GaAs can be well described with {ital D} =(43{plus_minus}25)exp[({minus}4.24{plus_minus}0.06 eV)/ {ital k}{sub B}{ital T}] over 6 orders of magnitude between 800 and 1225{degree}C under As-rich condition. No significant doping effects are observed in samples with their substrates doped with Te up to 4{times}10{sup 17} cm{sup {minus}3} or Zn up to 1{times}10{sup 19} cm{sup {minus}3}. Our results substantiate some of the findings in recent theoretical work. {copyright} {ital 1996 The American Physical Society.}