Low-temperature photoluminescence of in_0.14Ga _0.86As_0.13Sb_0.87 solid solution lattice matched to GaSb

A low-temperature photoluminescence (PL) study of liquid phase epitaxy grown undoped and Te-doped In_0.14Ga_0.86As _0.13Sb_0.87 layers lattice matched to n-type GaSb is reported. The quaternary solid solutions In_xGa_1-x As _ySb_12y are promising materials for the fabrication of optoelectronics devices operating in the spectral range of 3-5 μm because these alloys can form type II heterojunctions with both staggered and broken-gap alignments. The PL for the undoped InGaAsSb layer shows three narrow exciton-related peaks with narrow full width at half-maximum (FWHM), which is an evidence of the good crystalline quality of the epilayers. The PL spectrum for a slight Te-doped InGaAsSb layer shows a red shift, which is more remarkable for high excitation powers. When increasing the Te-doping in the quaternary alloys, the PL spectra show that the donor-to-acceptor radiative transition associated with neutral tellurium and a neutral acceptor is dominant, although the band-to-band transition is present too.