High resistivity and picosecond carrier lifetime of GaAs implanted with MeV Ga ions at high fluences

Abstract

Rutherford backscattering spectrometry-channeling, double-crystal x-ray diffraction, optical absorption studies, and electrical measurements have been carried out on 2 MeV Ga-implanted GaAs at fluences of 1×1015 and 5×1015 cm−2. Implanted samples exhibited a strain field associated with implantation-induced damage, low resistivity due to hopping conduction and mobilities of about 1 cm2/V s. Annealing of these samples at 600 °C caused substantial recovery of postimplant damage and an increase of resistivity of more than four orders of magnitude, with mobility up to about 2600 cm2/V s. Photocarrier lifetime of annealed samples is in the few picoseconds range. These properties are strikingly similar to those of arsenic implanted GaAs, suggesting that arsenic precipitates are unlikely to be solely responsible for short carrier lifetime in the latter case. Thus Ga-implanted GaAs may be an interesting prospect for fast optoelectronic device applications.