Uniform and Duty Cycle Tunable Photonic Crystal LEDs Fabricated by Intermediate Mask Layer: Soft UV Nanoimprint Lithography

Abstract

As an improvement of the conventional nanoimprint lithography, an intermediate mask layer process is invited for photonic crystal pattern transfer on LEDs. Benefit from the smooth effect of the under-layer resist, uniform photonic crystal structure is successfully transferred to the p-GaN surface. The intermediate SiO2 layer has a high etching selectivity to the under-layer resist, which can be used to fabricate nanostructures with tunable duty cycle via one single initial mold. The photonic crystal LED fabricated by the process of intermediate mask layer nanoimprint lithography shows a 3.31 fold PL enhancement to that of the un-patterned LED.