# Optical Response of Aged Doped and Undoped GaAs Samples

## TL;DR

This paper examines how aging affects the optical properties of doped and undoped gallium arsenide (GaAs) samples over 26 years.

## Contribution

The study reveals that aging introduces As vacancies linked to deep energy levels and forms complexes with Ge and Sn impurities.

## Key findings

- Aging introduces As vacancies that form deep energy levels associated with the L band.
- The concentration of vacancies reached up to 10^17 cm−3 over 26 years.
- Vacancies form complexes with Ge and Sn doping impurities.

## Abstract

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.