Selective epitaxial growth of InGaN alloys was performed by metalorganic chemical vapor deposition (MOCVD). Templates consisted of arrays of circular etched holes in a SiO2 mask layer, with pre-grown GaN hexagonal pyramid structures. The room temperature (300 K) photoluminescence (PL) peak wavelength increased with increasing mask-opening spacing for a constant mask-opening diameter. For 5 mu m diameter pyramids, peak PL wavelengths ranged from 457 to 505 nm for mask opening spacings of 6 to 13 mu m, compared to PL peak wavelength of 420 nm for a planar reference sample. (C) 1998 Elsevier Science B.V. All rights reserved.