Photoluminescence properties of p-type InGaAsN grown by RF plasma-assisted molecular beam epitaxy

We have investigated the photoluminescence (PL) properties of p-type InGaAsN epilayers grown by a radio frequency (RF) plasma-assisted nitrogen source in a molecular beam epitaxy (MBE) system. The low temperature PL spectra exhibited both a LE emission peak at around 1000 nm and a broad deep band at 1200–1700 nm. As temperature increases, the LE peak position redshifts and its intensity becomes weaker and disappears at 100 K. The deep PL band may originate from recombinations associated with N-related traps. The hole concentration dependence of the integrated intensity ratio of the LE emission peak to the deep PL band at 5 K can be separated into two doping regimes. At light doping regime (1.0×1016 cm-3<p<2.1×1018 cm-3), this ratio is linearly proportional to the hole concentration and is explained in terms of neutral-acceptor-bound excitons. At high doping regime (2.1×1018 cm-3<p<1.2×1019 cm-3), the LE emission could possibly originate from mechanisms arising from hole degeneracy. This intensity ratio saturates at high doping regime.