Low temperature photoluminescence of tellurium-doped GaSb grown by molecular beam epitaxy

We present the first systematic study of photoluminescence (PL) of GaSb grown by molecular beam epitaxy and Te doped at levels ranging from non-intentional to high. The PL spectra show features that gradually evolve with the doping Level. The main structure of the PL. spectra of the nominally undoped sample is a band attributed to the native double acceptor defect, which determines the p-type conductivity. rn doped samples, the evidence of Levels directly connected with tellurium has been found. At low doping levels we observe the recombination of free holes with electrons bound to the Te hydrogenic donor, while in heavily doped samples the dominant feature is a deep PL band attributed to a complex involving incorporated Te and structural defects. The observed blue shift of the PL bands as the doping lever increases is consistent with the occurrence of band-filling effects.