Vertical GaN nanocolumns grown on graphene intermediated with a thin AlN buffer layer

Authors:
Publisher website
Google Scholar
Abstract
We report on the self-assembled growth of high-density and vertically-oriented n -doped GaN nanocolumns on graphene by radio-frequency plasma-assisted molecular beam epitaxy. Graphene was transferred to silica glass, which was used as the substrate carrier. Using a migration enhanced epitaxy grown AlN buffer layer for the nucleation is found to enable a high density of vertical GaN nanocolumns with c -axis growth orientation on graphene. Furthermore, micro-Raman spectroscopy indicates that the AlN buffer reduces damage on the graphene caused by impinging active N species generated by the radio-frequency plasma source during the initial growth stage and nucleation of GaN. In addition, the grown GaN nanocolumns on graphene are found to be virtually stress-free. Micro-photoluminescence measurements show near band-edge emission from wurtzite GaN, exhibiting higher GaN bandgap related photoluminescence intensity relative to a reference GaN bulk substrate and the absence of both yellow luminescence and excitonic defect emission. Transmission electron microscopy reveals the interface of GaN nanocolumns on graphene via a thin AlN buffer layer. Even though the first few monolayers of AlN on top of graphene are strained due to in-plane lattice mismatch between AlN and graphene, the grown GaN nanocolumns have a wurtzite crystal structure without observable defects. The results of this initial work pave the way towards realizing low-cost and high-performance electronic and optoelectronic devices based on III-N semiconductors grown on graphene.
Funding Information
  • Japan Society for the Promotion of Science (KAKENHI (Grant No. 24000013))
  • NORTEM infrastructure (197405)
  • Norges Forskningsråd (NANO2021 (Grant No. 259553), Norwegian Micro- and Nano-Fabricati, Norwegian PhD Network (FORSKERSKOLE)

This publication has 61 references indexed in Scilit: