Nonpolar ${m}$ -Plane InGaN/GaN Micro-Scale Light-Emitting Diode With 1.5 GHz Modulation Bandwidth

We demonstrate a high-speed nonpolar m-plane InGaN/GaN micro-scale light-emitting diode (LED) with a record electrical -3 dB modulation bandwidth of 1.5 GHz at a current density of 1 kA/cm². A differential carrier lifetime (DLT) of 200 ps at 1 kA/cm² was extracted using a rate-equation model. The short DLT is attributed to the high electron-hole wave function overlap in polarization-free nonpolar InGaN/GaN quantum wells, which leads to a higher spontaneous emission rate at low current densities compared to polar c-plane quantum wells. LEDs with improved high-speed performance at low current densities will help to reduce power dissipation and increase efficiency in Gb/s visible-light communication systems.

I. Introduction

Mobile communications traffic is increasing beyond the limit where radio frequency (RF) technology can support the demand [1], [2]. Thus, there is a need for new supplementary wireless technologies to cooperate with existing RF networks [3]. Visible-light communication (VLC) is a promising candidate for next-generation (5G and beyond) network systems, especially for indoor applications [4], [5]. InGaN/GaN light-emitting diodes (LEDs) are attractive sources for VLC since they have the potential to simultaneously provide efficient lighting and data communication at minimal extra cost and power consumption [1], [6]. However, commercially available lighting-class LEDs have low modulation bandwidths (<50 MHz) due to their large size and cannot easily provide the Gb/s data rates needed for VLC.