Fabrication of an a-plane AlGaN quantum well on r-plane sapphire

Nonpolar AlGaN light-emitting diodes have been attracting much attention due to their potential for realizing optoelectronic devices with high efficiency and stability. However, few studies have been reported on the optical properties of nonpolar AlGaN quantum wells (QWs) on sapphire because of the difficulty in the growth. Here, we report the fabrication of an a-plane AlGaN QW on r-plane sapphire using high-temperature growth method. An Al(Ga)N layer with smooth morphology was obtained at high temperature and low V/III ratio compared to the conventional conditions. An NH
₃
flow rate played an important role in controlling the Al content of AlGaN at high temperature. An a-plane QW showed clear luminescence in the UVC range at room temperature.