GaSb is the most suitable substrate in the epitaxial growth of mixed semiconductors of GaSb system.In this work,Te-doped GaSb bulk crystals with different doping concentration have been annealed at 550 ℃ for 100 h in ambient antimony.The annealed samples have been studied by Hall effect measurement,infrared (IR) optical transmission,Glow discharge mass spectroscopy (GDMS) and photoluminescence (PL) spectroscopy.After annealing,Te-doped GaSb samples exhibit a decrease of carrier concentration and increase of mobility,along with an improvement of below gap IR transmission.Native acceptor related electrical compensation analysis suggests a formation of donor defect with deeper energy level.The mechanism of the variation of the defect and its influence on the material properties are discussed.