Long-Wavelength Semipolar (11-22) InGaN/GaN LEDs with Multi-Gb/s Data Transmission Rates for VLC

Abstract

Monolithic integration of red, green, and blue (RGB) LEDs is crucial for white light visible light communications (VLC), display technology, and general illumination but is intrinsically limited by the fundamental differences between the InGaN and AlGaInP epitaxial material systems typically used for visible wavelength emission. Increasing the indium content in traditionalc-plane InGaN/GaN to achieve longer wavelength LEDs enhances the piezoelectric-induced polarization resulting in a low quantum efficiency and long radiative lifetimes. These issues can be resolved by growing along a nonpolar or semipolar orientation. This paper demonstrates the feasibility of the (11-22) semipolar LEDs for long-wavelength VLC with an additional capability of monolithic integration to produce a single white light RGB chip. Based on our high-performance semipolar InGaN/GaN LEDs, we report record data transmission rates of 4.22 Gb/s, 3.72 Gb/s, and 336 Mb/s under the forward error correction (FEC) threshold standard for reliable communication for our green (515 nm), yellow (550 nm), and amber (600 nm) semipolar LEDs using adaptively bit-loaded DC-biased optical orthogonal frequency division multiplexing (DCO-OFDM).