Ga self-diffusion in GaAs isotope heterostructures

Isotopically controlled GaAs heterostructures have been used to study Ga self-diffusion with secondary-ion mass spectrometry. 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 D = (43 +/- 25) exp[(-4.24 +/- 0.06 eV)/k(B)T] over 6 orders of magnitude between 800 and 1225 degrees C under As-rich condition. No significant doping effects are observed in samples with their substrates doped with Te up to 4 x 10(17) cm(-3) or Zn up to 1 x 10(19) cm(-3). Our results substantiate some of the findings in recent theoretical work.