Improvement of Light Output Power in InGaN/GaN Light-Emitting Diodes with a Nanotextured GaN Surface Using Indium Tin Oxide Nanospheres

An etching process and indium tin oxide (ITO) nanospheres were used to fabricate nanotexturing on a GaN surface in InGaN/GaN multiple-quantum well light-emitting diodes (LEDs) to improve the light output power ITO nanospheres can be easily obtained by a simple wet etching process owing to the relatively weak binding energy at the grain boundary and at the interface between the ITO layer and the GaN surface. Inductively couples plasma (ICP) treatment is carried out with the help of ITO nanospheres, used as patterning mask, to nanotexture the GaN surface. A simple process is proposed for GaN-texturing on all possible sides, including the sidewall. The light extraction efficiency of InGaN/GaN LEDs is significantly improved owing to the possibility of a high level of light scattering at the textured surface. Thus, the light output power of the nanotextured LEDs was increased by 33% compared with that of conventional LEDs at an injection current of 20 mA. (C) 2009 The Japan Society of Applied Physics