Photoluminescence of InAs0.04P0.67Sb0.29

Abstract

We report the results of a detailed photoluminescence (PL) study on quaternary InAs0.04P0.67Sb0.29 grown by gas-source molecular-beam epitaxy. The main PL peak at 10 K shows a transition energy that is lower than the calculated energy gap by 0.223 eV, which is attributed to the tail states recombination. Another PL band, which emerges as the temperature increases, is assigned to the self-activated luminescence from defect centers. Its features, namely, nearly temperature-independent peak energy, Gaussian-like lineshape, and square-root-of- temperature-dependent linewidth, can be illustrated by the configuration coordinate model. The vibration energy, calculated from the linewidth at low temperature, is 0.022 eV for the excited state of the defect centers. The self-activated luminescence shows a thermal quenching behavior that is usually exhibited by amorphous semiconductors, indicating that the defects are related to the compositional disorder. The defects responsible for the luminescence are most likely complexes consisting of a substitutional carbon and an In vacancy.