DLTS detection of hole traps in MBE grown ρ-GaAs using schottky barrier diodes

The presence of hole traps has been studied by deep level transient spectroscopy (DLTS) characterization of low carrier densityp-type GaAs grown by MBE on p⁺-GaAs substrates using Al and Co Schottky contacts. The results obtained indicate the presence of several hole traps with energy levels of between 0.06 and 0.65 eV above the valence band in concentrations up to 2 × 10¹²/cm³. Some of these defects,e.g. Cu, are ascribed to system-, source-or substrate-related impurities, but the origin of several other defects is unknown.