Single-crystal GaN thin films were successfully grown on porous Si (Psi) substrates using metalorganic chemical vapor deposition. The full-width at half-maximum (FWHM) of the asymmetric rocking curve for a GaN film on a Psi substrate was narrower than that for a GaN film on a normal flat-Si substrate (Flat-Si), whereas the FWHM of the symmetric one is broader. Compared with a GaN film on Flat-Si, the extent of wafer bending was reduced and the band-edge emission from GaN was enhanced. Moreover, the tensile stress in the film was significantly reduced. (C) 2008 Elsevier B.V. All rights reserved.