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Structural and optical properties of cubic GaN films on high-thermal conductivity substrates

At a Glance

Section titled ā€œAt a Glanceā€
MetadataDetails
Publication Date2025-01-15
JournalJournal of Applied Physics
AuthorsJaime A. Freitas, James C. Culbertson, David F. Storm, Nadeemullah A. Mahadik, Neeraj Nepal
InstitutionsUnited States Naval Research Laboratory
Citations1

Abstract

Section titled ā€œAbstractā€

A thin cubic-GaN epitaxial layer was grown by plasma-assisted molecular-beam epitaxy directly on a (100) cubic-boron-nitride nucleation layer that was previously deposited on a (100)-oriented, type IIA, single-crystal chemical-vapor deposition diamond substrate. X-ray diffraction measurements verified that (100)-plane zincblende is the dominant crystal structure of the GaN layer, with a small contribution from the wurtzite phase in some sample regions. Detailed atomic force microscopy and Raman scattering measurements confirmed the XRD findings. Low temperature photoluminescence spectra show a dominant emission line near 3.12 eV and a weaker emission line near 3.21 eV. The former is assigned to a recombination process involving electrons bound to shallow donors with holes bound to shallow acceptors (donor-acceptor pair recombination process). The latter, which becomes dominant at temperatures above 50 K, is assigned to a recombination process involving the annihilation of excitons bound to shallow impurities. Room temperature transmission measurements yielded a direct bandgap of 3.23 eV, which is close to the reported values for c-GaN. These results confirm that cubic-GaN was successfully deposited on a high thermal-conductivity diamond substrate. This opens the door to exploring the potential of cubic-GaN devices for high-power applications, given that large area diamond substrates are becoming available.

Tech Support

Section titled ā€œTech Supportā€

Original Source

Section titled ā€œOriginal Sourceā€

References

Section titled ā€œReferencesā€
  1. 1997 - The near band edge photoluminescence of cubic GaN epilayers [Crossref]
  2. 2005 - Thick cubic GaN film grown using ultra-thin low-temperature buffer layer by RF-MBE [Crossref]
  3. 1998 - Metalorganic vapor phase epitaxy growth of high quality cubic GaN on GaAs (100) substrates [Crossref]
  4. 2012 - Optical properties of cubic GaN from 1 to 20ā€‰eV [Crossref]
  5. 2018 - High internal quantum efficiency ultraviolet emission from phase-transition cubic GaN integrated on nanopatterned Si(100) [Crossref]
  6. 2022 - Structural and optical properties of cubic GaN on U-grooved Si (100) [Crossref]
  7. 2016 - Critical issues for homoepitaxial GaN growth by molecular beam epitaxy on hydride vapor-phase epitaxy-grown GaN substrates [Crossref]
  8. 2022 - Mg-facilitated growth of cubic boron nitride by ion beam-assisted molecular beam epitaxy [Crossref]
  9. 2017 - Surface preparation of freestanding GaN substrates for homoepitaxial GaN growth by rf-plasma MBE [Crossref]

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