The performance improvement of AlGaN/GaN heterojunction by using nano-patterned sapphire substrate

Abstract

AlGaN/GaN heterojunction structures grown on nano-scale patterned sapphire substrates and planar sapphire substrates were investigated. The X-ray diffraction rocking curves indicated an improvement of crystalline quality by using sapphire substrate with concave nano-scale patterns. The surface morphology improvement of samples was characterized using atomic force microscope and scanning electron microscope. The transmission electron microscope results showed a significant dislocation reduction. The Hall-effect measurement confirmed that the mobility of two-dimensional electron gas was obviously improved.