High efficiency blue InGaN microcavity light-emitting diode with a 205 nm ultra-short cavity

Abstract

High-efficiency blue InGaN-based semipolar (20-2-1) ultra-short microcavity light-emitting diodes (MC-LEDs) with a cavity length of 205 nm were demonstrated. A peak external quantum efficiency (EQE) of 7.3%, the value of which is almost the same as 10% of conventional c-plane micrometer-sized microlight-emitting diodes with a device thickness of ∼5 μm grown on the sapphire substrate, was achieved. The emission wavelength is 431 nm at the current density of 297 A/cm2. In order to obtain high-efficiency MC-LEDs, a sidewall treatment was performed by using buffered hydrofluoric acid and phosphoric acid (H3PO4) to remove the dry etching residue and the surface damage. The demonstration of MC-LEDs with a high EQE and a single mode emission should pave the way for the application to display and others.