InGaN light-emitting diodes with band-pass-filter-like GaN : Si nanoporous structures

Abstract

InGaN-based light-emitting diodes (LEDs) with both GaN : Si nanoporous and air-gap structures were fabricated through a wet lateral etching (LE) process. Light output power of the LE-LED structure was enhanced by 58% compared with a non-treated LED structure, due to the increased light extraction from the GaN : Si nanoporous and air-gap structure. Optical transmittance of the structure was analysed using photoluminescence from the LED epitaxial layers. The transmittance of the LE-LED was measured to be 2.56 times for the blue emission and 0.43 times for the yellow emission, compared with the non-treated LED structure at a detection angle of 35° from the lateral direction. The optical properties of the GaN : Si nanoporous structure were similar to a band-pass filter with a 460 nm centre wavelength and a 70 nm bandwidth, which effectively enhanced the light-extraction efficiency in InGaN LEDs.