Characterization of nonpolar a-plane InGaN/GaN multiple quantum well using double nanopillar SiO sub(2) mask

The characteristics of nonpolar a-plane (1120) GaN (a-GaN) grown using single and double nanopillar SiO sub(2) masks were investigated. The two nanopillar SiO sub(2) masks were directly fabricated on an r-plane sapphire substrate and a-GaN by the epitaxial lateral overgrowth (ELOG) technique. Through the use of the single and double nanopillar SiO sub(2) masks, the crystalline quality and optical properties of a-GaN were markedly improved because of the nanoscale ELOG effect and a number of voids in the single and double nanopillar SiO sub(2) mask areas in comparison with the planar sample. The submicron pit densities of the planar, single, and double nanopillar mask samples were ~2 x 10 super(9), ~7 x 10 super(8), and ~4 x 10 super(8)cm super(-2), respectively. The internal quantum efficiency (IQE) values at room temperature of three-period InGaN/GaN multiple quantum wells (MQWs) grown using the planar, single, and double nanopillar masks were 45, 60, and 68% at a carrier concentration of 1.0 x 10 super(18)cm super(-3), respectively.