The growth of Al0.85Ga0.15P on GaP using gas source molecular beam epitaxy is investigated using in situ highenergy electron diffraction, high-resolution x-ray diffraction, atomic-force microscopy, and scanning electron microscopy. Growth temperature and phosphorus flw.c were varied. The 1.0-mu m AlGaP films were grow On a GaP buffer layer and capped with GaP. The investigation indicates that a growth temperature of 490 degrees C and a cracked PH3 flux of 2.7 sccm resulted in the best AlGaP quality, while maintaining very good GaP quality. (C) 2015 Elsevier B.V. All rights reserved.