Free-carrier lifetime and deep-level luminescence in semi-insulating GaAs: The influence of indium doping and growth in a magnetic field

Abstract

The influence of In doping and/or of growth in a magnetic field on the properties of Czochralski-grown semi-insulating GaAs wafers is investigated. We determine the spatial distribution of the free-carrier lifetime by time-resolved luminescence in the ps regime. The results are compared with the spatial distribution of the near-band-edge and deep-level luminescence. The macroscopical and microscopical homogeneity of the carrier lifetime and the luminescence intensities are improved by the growth in a magnetic field. Indium doping leads to similar improvements and additionally to an increase of the absolute value of the lifetime. The combination of In doping and growth in a magnetic field gives the best results.