Selective area growth of Ga-polar GaN nanowire arrays by continuous-flow MOVPE: A systematic study on the effect of growth conditions on the array properties

Site-controlled growth of GaN nanowires (NWs) on GaN-on-sapphire templates with a patterned SiN mask has been carried out by metalorganic vapor phase epitaxy using a continuous-flow growth mode. A low V/III ratio compared to that used for GaN layer growth, combined with low precursor flow rates for both Ga and N precursors, has been used to promote the nanowire growth on Ga-polar substrates. The lateral growth rate, that is, perpendicular to the c-axis, could be further controlled using appropriate growth temperatures and H₂/N₂ ratios. Besides, the influence of the pattern geometry on the nanowire aspect ratio and size homogeneity has been addressed.