Improved light extraction efficiency on GaN LEDs by an In2O3 nano-cone film

Abstract

A bottom up method for the fabrication of a roughened transparent conductive layer (TCL) to accomplish a prominent enhancement in light extraction from GaN-based blue light emitting diodes (LEDs) has been developed. The nanostructured transparent conductive oxide (TCO) film was obtained by thermal oxidation of InN nanocones (NCs) grown beforehand into In₂O₃ NCs in a tube furnace at 550 °C, beyond the dissociation temperature of InN. A two-fold increase in the light output power of the LED with the In₂O₃ NCs TCL was achieved compared to that of an LED using a conventional Ni/Au TCL. Our work proposes a simple, useful and low thermal budget route to form a roughened In₂O₃ NCs film used as the TCL to realize a prominent enhancement in light extraction from LEDs. Based on the capability of the low temperature fabrication process of roughened In₂O₃ TCLs, our proposed method is suitable for industrial mass manufacture.