A top-down approach for fabrication of nanorods on gan-based leds using self-assembled Ni

Abstract

In optoelectronic devices such as LEDs, LASERs, strain-induced piezoelectric polarization occurs in the structure because of large lattice mismatch occurs between sapphire substrate and GaN layers. This degrades the performance of these devices due to strain-induced piezoelectric polarization. Nanostructuring can reduce this stress due to reduction in quantum-confined stark effect (QCSE) and strain-releasing effect. We demonstrate a top-down approach for fabricating GaN nanorods on LED using self-assembled nickel as an etching mask during reactive ion etching (RIE). The self-assembled Ni islands were formed by rapid thermal annealing at 850 °C for 1 min followed by RIE. The shape and morphology of GaN nanorods were studied using scanning electron microscopy (SEM). We realized vertical array of nanorods with dimensions varying from 90–200 nm.