We investigated the growth and optical properties of GaSb quantum dots (QDs) on GaAs (311)A substrates. We mounted GaAs (311)A and (100) substrates simultaneously on a molybdenum holder and grew GaSb QDs by molecular beam epitaxy (MBE). By atomic force microscopic studies, it was found that GaSb QDs grown on (311)A are smaller in size and their density is higher than that on (100). In photoluminescence (PL) measurements, a broad and overlapping PL peak originating from QDs is observed in both (311)A and (100) samples. The peak energy of the (311)A sample is lower than that of the (100) sample, although the size of QDs on GaAs (311)A is smaller than that on (100). This indicates that less residual As atoms are incorporated into QDs in the (311)A sample than those in the (100) sample. We also grew GaSb QDs at various substrate temperatures T-s and examined how T-s affects the QD shape and density. (c) 2012 Elsevier B.V. All rights reserved.