An in-depth optimization of growth conditions and investigation of optical properties of GaAsSb quantum well (QW) on GaAs-through different designs of barrier and cladding layers grown by molecular beam epitaxy (MBE-are reported. Optimal MBE growth temperature of GaAsSb QW is found to be 470 +/- 10 degrees C. GaAsSb/GaAs QW with similar to 0.36 Sb mole fraction has a weak type-II band alignment with a valence band offset ratio, Q(V) around 1.06. A full-width at half-maximum (FWHM) of similar to 60 meV in room temperature (RT) photoluminescence (PL) spectrum indicates less than 20 meV fluctuation in electrostatic potential. Samples grown under optimal conditions do not exhibit any blueshift of peak in RT-PL spectra under varying excitation intensities. (c) 2009 Elsevier B.V. All rights reserved.