Abstract
Temperature and excitation dependences of photoluminescence (PL) spectra of a slightly In-doped CdTe crystal were investigated, particularly in the spectral range of the "1.1 eV" PL band, i.e. in the interval of 0.9-1.25 eV. Both above-bandgap and below-bandgap excitations were employed.
Three components of the "1.1 eV" band with the PL maxima at around 1.19 eV, 1.13 eV, and 1.03 eV were distinguished. The component with a PL maximum at 1.19 eV vanishes above 40 K.
It can be attributed to a recombination of a thermally unstable state localized at a defect. The excitation spectrum of the second component with a maximum at 1.13 eV indicates that a transition in a deep localized center takes place.
The "1.13 eV" component prevails at higher temperatures with below-bandgap excitation. The "1.03 eV" component can be related to an effective recombination center, probably to a complex of deep donor and deep acceptor.
This component is the strongest one at higher temperatures and under above-bandgap excitation. Our present knowledge does not allow us to attribute the PL spectra to particular defects.