It was experimentally observed that the presence of indium solder between the backside of GaSb substrates and the molybdenum block has a significant effect on the molecular, beam epitaxial (MBE) growth of antimony compounds. X-ray diffraction and photoluminescence characterization results show that material quality was substantially improved when a custom-made substrate holder with which to avoid indium solder between GaSb substrate and molybdenum block for mounting was used. Strain compensated InGaAsSb/AlGaAsSb laser diode devices were grown by MBE. A 2.82 mum emission wavelength and a 660 A/cm(2) threshold current density. were obtained in the pulsed mode at room temperature. (C) 2004 American Vacuum Society.