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 e V)/k_B T] over 6 orders of magnitude between 800 and 1225 ° C under As-rich condition. No significant doping effects are observed in samples with their substrates doped with Te up to 4 × 10¹⁷ cm⁻³ or Zn up to 1 × 10¹⁹ cm⁻³. Our results substantiate some of the findings in recent theoretical work.