Strained InAsyP1-y(y:0.3-0.75)/InP multiple quantum wells were grown on InP substrates by solid source molecular beam epitaxy using arsenic tetramer (As-4) and dimer (As-2). X-ray diffraction measurement and simulation reveal the high structural quality of the samples regardless of the arsenic species used. while the incorporation efficiency or As, is found to be higher than that of As-4. Room temperature and 10 K photoluminescence (PL) measurements were performed to optically examine the samples. The room temperature PL properties in the whole composition range inspected are obviously improved for the samples grown using As, instead of AS(4), but the 10 K PL properties are comparable. (C) 2002 Elsevier Science B.V. All rights reserved.