Thin Solid Films, Vol.520, No.1, 437-441, 2011
Enhancement of light output power in GaN-based light-emitting diodes using indium tin oxide films with nanoporous structures
We fabricated GaN-based light-emitting diodes (LEDs) with a transparent ohmic contact made from nanoporous indium tin oxide (ITO). The nanoporous structures are easily made and controlled using a simple wet etching technique. The transmittance, sheet resistance, and root-mean-square surface roughness of the nanoporous ITO films are correlated strongly with the etch times. On the basis of the experimental values of these parameters, we choose an optimum etch time of 50 s for the fabrication of LEDs. The wall-plug efficiency of the LEDs with nanoporous ITO is increased by 35% compared to conventional LEDs at an injection current of 20 mA. This improvement is attributed to the increase in light scattering at the nanoporous ITO film-to-air interface. (C) 2011 Elsevier B.V. All rights reserved.
Keywords:Light-emitting diodes;Nanoporous oxide;Indium tin oxide;Gallium nitride;Scanning electron microscopy