High-Efficiency InGaN/GaN Quantum Well-Based Vertical Light-Emitting Diodes Fabricated on β-Ga2O3 Substrate

Mufasila M Muhammed; Norah Alwadai; Sergei Lopatin; Akito Kuramata; Iman S Roqan

doi:10.1021/acsami.7b09584

High-Efficiency InGaN/GaN Quantum Well-Based Vertical Light-Emitting Diodes Fabricated on β-Ga₂O₃ Substrate

ACS Appl Mater Interfaces. 2017 Oct 4;9(39):34057-34063. doi: 10.1021/acsami.7b09584. Epub 2017 Sep 22.

Authors

Mufasila M Muhammed¹, Norah Alwadai¹, Sergei Lopatin², Akito Kuramata³, Iman S Roqan¹

Affiliations

¹ King Abdullah University of Science and Technology (KAUST) , Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia.
² King Abdullah University of Science and Technology (KAUST) , Imaging and Characterization Core Lab, Thuwal 23955-6900, Saudi Arabia.
³ Tamura Corporation and Novel Crystal Technology, Inc. , Sayama, Saitama 350-1328, Japan.

PMID: 28892352
DOI: 10.1021/acsami.7b09584

Abstract

We demonstrate a state-of-the-art high-efficiency GaN-based vertical light-emitting diode (VLED) grown on a transparent and conductive (-201)-oriented (β-Ga₂O₃) substrate, obtained using a straightforward growth process that does not require a high-cost lift-off technique or complex fabrication process. The high-resolution scanning transmission electron microscopy (STEM) images confirm that we produced high quality upper layers, including a multiquantum well (MQW) grown on the masked β-Ga₂O₃ substrate. STEM imaging also shows a well-defined MQW without InN diffusion into the barrier. Electroluminescence (EL) measurements at room temperature indicate that we achieved a very high internal quantum efficiency (IQE) of 78%; at lower temperatures, IQE reaches ∼86%. The photoluminescence (PL) and time-resolved PL analysis indicate that, at a high carrier injection density, the emission is dominated by radiative recombination with a negligible Auger effect; no quantum-confined Stark effect is observed. At low temperatures, no efficiency droop is observed at a high carrier injection density, indicating the superior VLED structure obtained without lift-off processing, which is cost-effective for large-scale devices.

Keywords: electroluminescence; gallium oxide; scanning transmission electron microscopy; time-resolved photoluminescence; vertical light emitting diode.