Multi-emission from InGaN/GaN multi-quantum wells grown on hexagonal GaN microstructures

GaN hexagonal microstructures with InGaN/GaN multi-quantum wells were fabricated by using the selective metal organic chemical vapor deposition technique on dot-patterned GaN/sapphire(0001) substrates. The shape of these GaN microstructures was strongly related to the formation of self-limited (0001) facet with various growth conditions, which affect the Ga diffusion and surface reaction on the GaN surface. InGaN/GaN multi-quantum well structures on hexagonal GaN microstructures were selectively grown and characterized by scanning electron microscopy, photoluminescence, cathodoluminescence and transmission electron microscopy measurements. Blue emission was obtained from six (11̄01) facets as well as the flat (0001) facet, while yellow luminescence was observed at lateral overgrown region through the six (11̄01) side-walls.