Polarity-inverted lateral overgrowth and selective wet-etching and regrowth (PILOSWER) of GaN.

On an SiO-patterned c-plane sapphire substrate, GaN domains were grown with their polarity controlled in accordance with the pattern. While N-polar GaN was grown on hexagonally arranged circular openings, Ga-polar GaN was laterally overgrown on mask regions due to polarity inversion occurring at the boundary of the circular openings. After etching of N-polar GaN on the circular openings by HPO, this template was coated with 40-nm Si by sputtering and was slightly etched by KOH.