Green electroluminescence using n-In2O3 nanorods formed on plasma surface treated p-GaN structure

Abstract

We demonstrate the green light-emitting diodes (LEDs) using n-In2O3 nanorods (NRs)/p-GaN based pn junction with an insertion of thin Ga2O3 layer. In order to form the oxide interfacial layer between n- and p-material, O2 plasma treatment was conducted on p-GaN surface. The X-ray photoelectron spectroscopy patterns clearly show the formation of thin Ga2O3 layer on p-GaN surface via O2 plasma treatment. After formation of Ga2O3 layer on p-GaN surface, water droplet contact angle is decreased from 55° to 39°, which means that the surface is converted toward to more hydrophilic properties. The In(OH)3 NRs with 300 nm-length and 150 nm-diameter are uniformly grown on plasma treated p-GaN surface by using hydrothermal method. After then, final In2O3 NRs were obtained by phase change from as-grown In(OH)3 NRs without the morphology change by calcination process. The electroluminescence of fabricated LEDs using n-In2O3/Ga2O3/p-GaN heterojunction shows the green emission (λ ∼ 554 nm) at forward bias condition. As a possible light emission mechanism from our suggested heterostructures, the various defects energy states mediated green emissions were considered with band diagram.