Semipolar {10 (1) over bar(3) over bar} GaN layers were grown on self-assembled SiO2 nanospheres sapphire (SSNS) by hydride vapor phase epitaxy. The RMS roughness was 1.1 nm for the scan of 20 is 20 mu m(2) and the striated surface morphology almost disappeared. The full widths at half maximum of on-axis X-ray rocking curves were 324 arcsec rocking toward the [30 (3) over bar(2) over bar] direction and 413 arcsec rocking toward the [1 (2) over bar 10] direction, respectively. Compared to the GaN layer grown on the planar sapphire, the reduction of the defect density of semi-GaN grown on SSNS, such as basal stacking faults, partial dislocations and perfect dislocations, was demonstrated by both X-ray rocking curves and low temperature photoluminescence. In addition, the Raman analyses also showed the partial relaxation of the stress using SSNS. (C) 2013 Elsevier B.V. All rights reserved.