GaN-Based Resonant-Cavity Light-Emitting Diodes Grown on Si.

Wen Chen,Qian Sun,Yongjin Wang,Jianxun Liu,Meixin Feng,Hui Yang,Xumin Gao,Yongjun Tang,Jian Wang

doi:10.3390/nano12010134

Abstract

GaN-on-Si resonant-cavity light-emitting diodes (RCLEDs) have been successfully fabricated through wafer bonding and Si substrate removal. By combining the chemical mechanical polishing technique, we obtained a roughness of about 0.24 nm for a scan area of 5 μm × 5 μm. The double-sided dielectric distributed Bragg reflectors could form a high-quality optical resonant cavity, and the cavity modes exhibited a linewidth of 1 nm at the peak wavelength of around 405 nm, corresponding to a quality factor of 405. High data transmission in free space with an opening in the eye diagram was exhibited at 150 Mbps, which is limited by the detection system. These results showed that GaN-based RCLEDs grown on Si are promising as a low-cost emitter for visible light communications in future.

Highlights

Academic Editor: Seiichi MiyazakiGaN-based resonant-cavity light-emitting diodes (RCLEDs) with narrow spectral width, stable peak wavelength, superior directionality, and high output-coupling efficiency [1,2,3,4] have shown great potential applications in various fields, such as line-of-sight visible light communications (VLCs), plastic optical fiber-based networks, optical scanners, speckle-free illumination, printers, and displays [5,6,7,8].Up to now, there have been no GaN-based RCLED products
For GaN-based RCLEDs with hybrid distributed Bragg reflectors (DBRs), about 40 pairs of GaN/AlGaN or GaN/InAlN DBRs are usually grown underneath the quantum wells (QWs) [9,10,11,12], which may induce high tensile stress and even micro-cracks, and increase the dislocation density, seriously reducing the internal quantum efficiency [13]
The GaN-based RCLED material was epitaxially grown on Si(111) substrate by metalThe GaN-based RCLED material was epitaxially grown on Si(111) substrate by metalorganic chemical vapor deposition

Summary

Introduction

Academic Editor: Seiichi MiyazakiGaN-based resonant-cavity light-emitting diodes (RCLEDs) with narrow spectral width, stable peak wavelength, superior directionality, and high output-coupling efficiency [1,2,3,4] have shown great potential applications in various fields, such as line-of-sight visible light communications (VLCs), plastic optical fiber-based networks, optical scanners, speckle-free illumination, printers, and displays [5,6,7,8].Up to now, there have been no GaN-based RCLED products. For GaN-based RCLEDs with hybrid distributed Bragg reflectors (DBRs), about 40 pairs of GaN/AlGaN or GaN/InAlN DBRs are usually grown underneath the quantum wells (QWs) [9,10,11,12], which may induce high tensile stress and even micro-cracks, and increase the dislocation density, seriously reducing the internal quantum efficiency [13]. For GaN-based RCLEDs with double-sided dielectric DBRs, the laser lift-off process is usually used to remove the sapphire substrates [14,15], which often causes high stress and even cracks, greatly affecting the device performance and yield. Si substrates match with the conductive Si submount in the coefficient of thermal expansion, which can greatly reduce the stress in the bonding process and improve the device performance

Methods

Results

Conclusion