Optical Response of Aged Doped and Undoped GaAs Samples

We studied epitaxial GaAs samples doped with Ge and Sn up to 1×1019 cm -3, which were stored in a dry and dark environment for 26 years. The optical response of the GaAs samples was determined through the photoluminescence and photoreflectance techniques, taken at different times: just after their fabrication in 1995, 2001 and 2021. The evolution of defects formed by the action of O 2 in the samples and their correlation with doping with Ge and Sn impurities were studied. We obtained the result that aging formed defects of type vacancies, mainly As, which produced energy levels of deep traps linked to the L band. The concentration of vacancies over the 26 years could be as large as 1017 cm -3, and these vacancies form complexes with doping impurities.