InGaN light‐emitting diodes with indium‐tin‐oxide sub‐micron lenses patterned by nanosphere lithography

– Q Zhang, KH Li, and HW Choi

AFM images showing nano‐lens with diameter of (a) 195 nm, (b) 310 nm, and (c) 500 nm; FE‐SEM images showing nano‐lens array in good packing order with diameter of (d) 195 nm, (e) 310 nm, and (f) 500 nm.

Applied Physics Letters, vol. 100, 6, pp. 061120 (2012)

Close‐packed micro‐lenses with dimensions of the order of wavelength have been integrated onto the indium‐tin‐oxide (ITO) layer of GaN light‐emitting diodes employing nanosphere lithography. The ITO lens arrays are transferred from a self‐assembled silica nanosphere array by dry etching, leaving the semiconductor layer damage‐free. An enhancement of up to 63.5% on optical output power from the lensed light‐emitting diode (LED) has been observed. Lens‐patterned LEDs are also found to exhibit reduced emission divergence. Three‐dimensional finite‐difference time‐domain simulations performed for light extraction and emission characteristics are found to be consistent with the observed results.

DOI: 10.1063/1.3684505