Enhanced Light Extraction in Wafer-Bonded AlGaInP-Based Light-Emitting Diodes via Micro- and Nanoscale Surface

Abstract—AlGaInP-based metal-bonding light-emitting diodes (LEDs) with micro- and nanoscale textured surface were inves-tigated. The device surface with microbowls and nanorods were formed by a chemical wet-etching and dry-etching technique for enhancing light-extraction purpose. The luminous intensity could be enhanced 65.8 % under 20-mA current injection as compared with the plane surface LEDs. The maximum wall-plug efficiency was achieved 14.1 % at 7.5-mA operation. Index Terms—AlGaInP light-emitting diodes (LEDs), light-extraction efficiency, metal bonding, silica nanoparticles, spin coating, surface textured. THE HIGH-EFFICIENCY light-emitting diodes (LEDs)of AlGaInP-based quaternary materials with a visible spectrum from red to yellow-green are widely applied for many applications such as optical communications light source, TFT-LCD back light, traffic signal, automotive, exterior light