Low- and high-energy photoluminescence from GaSb1−xBix with 0 < x ≤ 0.042.

Two photoluminescence (PL) peaks were observed in temperature-dependent PL spectra of GaSb_1−xBi_x layers with 0 < x ≤ 0.042. The high-energy (HE) peak was found to be associated with the bandgap-related emission in GaSb_1−xBi_x, since its energy corresponds to the bandgap determined from photoreflectance measurements. The low-energy (LE) peak was attributed to the optical transition between the conduction band and native acceptor states, and was observed at low temperatures where acceptor states are not occupied by electrons. With increasing temperature, the intensity of the LE peak is quenched with the activation energy corresponding to the energy difference between HE and LE peaks. [ABSTRACT FROM AUTHOR]