Molecular Beam Epitaxy of Low Temperature Grown GaAs Photoconductors

Abstract

ABSTRACTWe report on the characterization of Low Temperature (LT) epitaxial growth of GaAs photoconductors. Samples were characterized using electro-optic sampling, transient femtosecond reflectivity, transmission electron microscopy, and pulsed terahertz spectroscopy as a function of growth temperature, As4 flux, doping and anneal conditions. We find the strongest effect on pulsewidth to be the temperature of an ex-situ rapid thermal anneal. In addition we find evidence of a temperature threshold for As precipitation. For more than an order of magnitude change in As precipitate density we find no corresponding change in electrical pulsewidth. Doping to 1017/cm3 also produces no change in the measured electrical response.