Hole diffusion length investigation by photon and electron excitation of GaAs Schottky barriers

A hole diffusion length in liquid-encapsulated-Czochralski (LEC) GaAs monocrystals (Si-doped, n=1015-1016 cm-3) in the range (0.4-3.0) 10-4 cm, has been determined by photon and electron bombardment through semitransparent Au or Cr Schottky electrodes. A minority-carrier lifetime in the range (0.3-9.7) 10-9 s was estimated. Schottky barrier diodes with abrupt junctions giving optimum electrical characteristics were prepared. The absorption length of the examined samples was evaluated by optical transmission measurements. The diffusion length investigation, which was carried out by the steady-state surface photovoltage (SPV) and the scanning electron microscope electron-beam-induced current (SEM-EBIC) techniques, has been related to the spectral quantum efficiency of Schottky diodes. SPV and EBIC techniques are emphasized as complementary methods for the investigation of bulk photoeiectronic properties.