Carrier dynamics of InxGa1-xN/GaN multiple quantum wells grown on (-201) β-Ga2O3 for bright vertical light emitting diodes.

Mufasila Mumthaz Muhammed,Jian Xu,Nimer Wehbe,Iman Salem Roqan

doi:10.1364/oe.26.014869

Abstract

High-quality InxGa1-xN/GaN multi-quantum well (MQW) structures (0.05≤x≤0.13), are successfully grown on transparent and conductive (-201)-oriented β-Ga2O3 substrate. Scanning-transmission electron microscopy and secondary ion mass spectrometry (SIMS) show well-defined high quality MQWs, while the In and Ga compositions in the wells and the barriers are estimated by SIMS. Temperature-dependant Photoluminescence (PL) confirms high optical quality with a strong bandedge emission and negligble yellow band. time-resolved PL measurements (via above/below-GaN bandgap excitations) explain carrier dynamics, showing that the radiative recombination is predominant. Our results demonstrate that (-201)-oriented β-Ga2O3 is a strong candidate as a substrate for III-nitride-based vertical- emitting devices.

Highlights

GaN and III-nitride alloys (InN and AlN) have attracted great research interest over the past few years and have triggered cutting-edge innovations in solid-state lighting due to their outstanding material properties, including large and tunable direct energy bandgap, maximum electron velocities, very large heterojunction offsets, and high thermal and chemical stability [1]
Scanning-transmission electron microscopy and secondary ion mass spectrometry (SIMS) show well-defined high quality multi-quantum well (MQW), while the In and Ga compositions in the wells and the barriers are estimated by SIMS
Our results demonstrate that (−201)-oriented β-Ga2O3 is a strong candidate as a substrate for III-nitride-based vertical- emitting devices

Summary

Introduction

GaN and III-nitride alloys (InN and AlN) have attracted great research interest over the past few years and have triggered cutting-edge innovations in solid-state lighting due to their outstanding material properties, including large and tunable direct energy bandgap, maximum electron velocities, very large heterojunction offsets, and high thermal and chemical stability [1]. Lateral LEDs grown on sapphire substrate suffer efficiency droop and reliability issues due to high threading dislocation density (TDD) caused by a significant lattice mismatch (~14%) [4]and severe current crowding near the edge of the n-contact and the n-type GaN material [5,6]. There is no systematic study on the optical and structural properties on InGaN/GaN multiple quantum well (MQW) with different InN contents grown on (−201)-oriented β-Ga2O3 To address this gap in the current research, in this study, we systematically investigate the structural and optical quality of the InxGa1-xN/GaN MQWs (x = 0.05−0.13) grown by MOCVD without any quality enhancement techniques, such as the epitaxial lateral overgrowth, substrate patterning or nano-imprint lithography. We perform a detailed investigation of the characteristic carrier dynamics of the MQWs grown directly on β-Ga2O3 substrate

Experiment

Results and discussion

Conclusion