Improved Light Extraction Efficiency of Light-Emitting Diode Grown on Nanoscale-Silicon-Dioxide-Patterned Sapphire Substrate

A conical-shaped Si dioxide nano-pattern was employed to sapphire substrate in order to improve the light extraction efficiency of light-emitting diodes. The conical-shaped Si dioxide nano-patterns were fabricated on a 2-inch sapphire wafer using direct imprinting of hydrogen silsesquioxane material. A blue-LED structure was grown on conical-shaped silicon-dioxide nano-patterned sapphire substrates. Photoluminescence and electroluminescence measurements were used to confirm the effectiveness of the nanoscale Si oxide patterned sapphire. An improvement in the luminescence efficiency was observed when nanoscale Si oxide patterned sapphire substrate was used. 1.5 times higher PL intensity and 1.6 times higher EL intensity were observed for GaN LED structure grown on nanoscale Si oxide patterned sapphire, compared to LED structure grown on conventional flat sapphire wafer.