title: High-quality III-nitride films on conductive, transparent (2̅01)-oriented β-Ga2O3 using a GaN buffer layer.
abstract: We demonstrate the high structural and optical properties of InxGa1-xN epilayers (0 ≤ x ≤ 23) grown on conductive and transparent (01)-oriented β-Ga2O3 substrates using a low-temperature GaN buffer layer rather than AlN buffer layer, which enhances the quality and stability of the crystals compared to those grown on (100)-oriented β-Ga2O3. Raman maps show that the 2″ wafer is relaxed and uniform. Transmission electron microscopy (TEM) reveals that the dislocation density reduces considerably (~4.8 × 10(7) cm(-2)) at the grain centers. High-resolution TEM analysis demonstrates that most dislocations emerge at an angle with respect to the c-axis, whereas dislocations of the opposite phase form a loop and annihilate each other. The dislocation behavior is due to irregular (01) β-Ga2O3 surface at the interface and distorted buffer layer, followed by relaxed GaN epilayer. Photoluminescence results confirm high optical quality and time-resolved spectroscopy shows that the recombination is governed by bound excitons. We find that a low root-mean-square average (≤1.5 nm) of InxGa1-xN epilayers can be achieved with high optical quality of InxGa1-xN epilayers. We reveal that (01)-oriented β-Ga2O3 substrate has a strong potential for use in large-scale high-quality vertical light emitting device design.
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia.
authors.forename: M M
authors.initials: MM
authors.lastname: Muhammed
authors.affiliation: Imaging and Characterization Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
authors.forename: M A
authors.initials: MA
authors.lastname: Roldan
authors.affiliation: Tamura Corporation, Sayama, Saitama 350-1328, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yamashita
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom.
authors.forename: S-L
authors.initials: SL
authors.lastname: Sahonta
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia.
authors.forename: I A
authors.initials: IA
authors.lastname: Ajia
authors.affiliation: Tamura Corporation, Sayama, Saitama 350-1328, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Iizuka
authors.affiliation: Tamura Corporation, Sayama, Saitama 350-1328, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Kuramata
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom.
authors.forename: C J
authors.initials: CJ
authors.lastname: Humphreys
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia.
authors.forename: I S
authors.initials: IS
authors.lastname: Roqan