The Optical Properties of InGaN/GaN Nanorods Fabricated on (-201) β-Ga2O3 Substrate for Vertical Light Emitting Diodes

Jie Zhao,Xuecheng Wei,Tongbo Wei,Junxi Wang,Weijiang Li,Lulu Wang

doi:10.3390/photonics8020042

Abstract

We fabricated InGaN/GaN nanorod light emitting diode (LED) on (-201) β-Ga2O3 substrate via the SiO2 nanosphere lithography and dry-etching techniques. The InGaN/GaN nanorod LED grown on β-Ga2O3 can effectively suppress quantum confined Stark effect (QCSE) compared to planar LED on account of the strain relaxation. With the enhancement of excitation power density, the photoluminescence (PL) peak shows a large blue-shift for the planar LED, while for the nanorod LED, the peak position shift is small. Furthermore, the simulations also show that the light extraction efficiency (LEE) of the nanorod LED is approximately seven times as high as that of the planar LED. Obviously, the InGaN/GaN/β-Ga2O3 nanorod LED is conducive to improving the optical performance relative to planar LED, and the present work may lay the groundwork for future development of the GaN-based vertical light emitting diodes (VLEDs) on β-Ga2O3 substrate.

Highlights

In order to verify whether the strain of nanorod light emitting diode (LED) on β-Ga2 O3 substrate is released or not, the Raman measurements of the GaN/β-Ga2 O3 planar and nanorod LED are revealed, respectively, with a range of 450–750 cm−1 [21,22]
In order to verify whether the strain of nanorod LED on β-Ga2O3 substrate is released or not, the Raman measurements of the GaN/β-Ga2O3 planar and nanorod LED are revealed, respectively, with a range of 450–750 cm−1 [21,22]
We clearly observe that the peak position of the E2(high) phonon mode within the GaN/β-Ga2O3 planar and nanorod LED

Summary

Introduction

It is important to find an alternative substrate which can be used to fabricate light emitting diode (LED) devices with good lattice match, low dislocation density, appropriate optical and electrical properties, as well as high transparency in visible spectrum regions. The LEE of the nanorod or nanowire LEDs may be effectively improved since they avoid total internal reflection and prevent the lateral propagation of light-waveguide effects [20]. Based on these features, we fabricated the InGaN/GaN nanorod LED on β-Ga2 O3 substrate for vertical LED (VLED) by the SiO2 nanosphere lithography and dryetching techniques. The LEE of the nanorod LED is effectively improved compared with the planar LED on β-Ga2 O3 substrate

Experimental Procedures

Results and Discussion

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Conclusions