Deep-level photoluminescence studies on Si-doped, metalorganic chemical vapor deposition grown AlxGa1-xAs

Abstract

Deep-level photoluminescence (PL) studies were performed on Si-doped, metal organic chemical vapor deposition grown AlxGa1-xAs as a function of the most important growth parameters. The SiH4 input mole fraction, the V/III ratio, and the Al fraction were varied over a wide range, resulting in net charge carrier concentrations n ranging between 1.8×1016 and 4.5×1018 cm-3, Hall mobilities μH between 220 and 2400 cm 2/V s, and a solid Al fraction x between 0 and 0.72. Two novel PL emissions for AlxGa1-xAs in the energy range of 1.05-1.35 eV were recorded. By a systematic analysis of the growth conditions these emissions were attributed to SiGa-SiAs and Si Ga-VGa complexes. The behavior of the broad PL emission at 0.8 eV as a function of the growth parameters was studied systematically. It was demonstrated that this emission is not related to the DX center. Instead, there are strong indications that it should be attributed to an internal transition within a native, or oxygen-related defect.