ABSTRACT
Cathodoluminescence (CL) investigations on bulk SI GaAs samples taken from different sources reveal the presence of a deep level emission at 0.9eV at 77K, with an uncharacteristically narrow full-width at half maximum of 8me V. This chapter explains the dependence of this spectral emission on temperature and the electron beam parameters. These data point towards the presence of a material with bandgap 0.9eV inside the SI GaAs crystal lattice, as the origin for this emission. GaAs has been one of the very well studied materials among the compound semiconductors. The investigation of deep level defects in GaAs is very important, since it is these which control the minority carrier lifetime, an important consideration for optoelectronic devices. Investigation of GaAs with the CL technique has been limited mainly to the near band edge emissions, with very few studies of deep-level emissions. The chapter deals with the deep level emission, observed in the undoped SI GaAs samples.
