Enhancement of the light output of GaN-based light-emitting diodes with surface-patterned ITO electrodes by maskless wet-etching

Wet-etching-induced surface patterning of p-type indium tin oxide (ITO) electrodes has been investigated to improve the light output of GaN-based light-emitting diodes (LEDs). Etching of as-deposited ITO layers in a buffered-oxide-etch solution results in the formation of a high density of randomly distributed sphere-shaped protrusions (250–1100 nm in size). LEDs fabricated with the 7 s-etched ITO electrodes yield higher light output (by 31.7% at 20 mA) compared with LEDs made with unpatterned ITO electrodes. The improvement is attributed to the increased light escape probability via the randomly distributed sphere-shaped protrusions formed on the electrode surfaces.