Low-temperature photoluminescence from CdTe grown by hot-wall epitaxy on GaAs

Abstract
The low-temperature near-band-edge photoluminescence of thick (d≊36 μm) (100)CdTe epilayers grown on (100)GaAs substrates is investigated. Besides a dominating bound exciton emission, evidence for free-exciton emission (n=1 and 2) and two electron transitions (TETs) of donor-bound excitons is found. The defect involved in the TET is most likely a gallium-related donor. This is concluded from the TET line wavelength adopting recent bulk CdTe TET data. A new emission line at 781.4 nm (1586.7 meV) is observed. It is tentatively assigned to a TET of a free exciton.