The unstrained and high quality GaInAsSb/InP single quantum well (SQW) is successfully grown by MOVPE on InP substrate. High resolution X-ray diffraction (HRXRD) and secondary ion mass spectrometry (SIMS) with Cs+ ions as the primary beam are used for evaluation of material quality and determination of layer thickness. Low temperature (8 K) photoluminescence (PL) spectroscopy is used to characterize the SQW structure. Thermal annealing effect on the PL properties of GaInAsSb/InP SQW structure is performed and discussed in this paper. After 30 s annealing with temperatures 650, 750 and 850degreesC, the PL peak intensity is not changed and the PL peak energy blue shifts. Furthermore, the increased PL peak full width at half maximum (FWHM) after annealing indicates that the inhomogeneous alloyed region increases. (C) 2004 Published by Elsevier B.V.