Spatially Resolved Investigation of the Bandgap Variation across a β-(AlxGa1-x)2O3/β-Ga2O3 Interface by STEM-VEELS

Adrian Chmielewski, Ziling Deng, Parivash Moradifar, Leixin Miao, Yuewei Zhang, Akhil Mauze, Kleyser A. Lopez, Wolfgang Windl, Nasim Alem

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Alloying β-(AlxGa1-x)2O3 on a β-Ga2O3 substrate results in a heterojunction with a tunable bandgap, but is often plagued by defects in the interface region. In this work, using valence electron energy loss spectroscopy combined with density functional theory calculations, we identify a high concentration of cation interstitials at a β-(Al0.2Ga0.8)2O3/β-Ga2O3 interface and measure the optical absorption edge. We find a dip in the band edge of 0.1 eV depth and a width of around 15 nm on the β-Ga2O3 side of the interface with signs of noticeable electron probe delocalization broadening and discuss defect states versus excitons as its possible origins.

Original languageEnglish (US)
Pages (from-to)585-591
Number of pages7
JournalACS Applied Electronic Materials
Volume4
Issue number2
DOIs
StatePublished - Feb 22 2022

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Electrochemistry

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