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Investigation of the surface band structure and the evolution of defects in β-(AlxGa1−x)2O3.
- Source :
- Applied Physics Letters; 3/11/2024, Vol. 124 Issue 11, p1-6, 6p
- Publication Year :
- 2024
-
Abstract
- This study examines the electronic and luminescent properties of β-(Al<subscript>x</subscript>Ga<subscript>1−x</subscript>)<subscript>2</subscript>O<subscript>3</subscript> (0 ≤ x ≤ 0.42) thin films grown on (0001) sapphire using laser-MBE, with a focus on the evolution of defect energy levels and their impact on surface Fermi level pinning and luminescence. X-ray photoelectron spectroscopy (XPS) and cathodoluminescence (CL) have been employed to analyze surface band bending and defect evolution as a function of aluminum content. The results have revealed a pinned Fermi level at 3.6 eV above the valence band maximum despite the increase in the bandgap. The consequent upward band bending has been confirmed by a peak shift in the core level XPS. The defects that lead to the Fermi level pinning effect are attributed to E2<superscript>*</superscript>, which is related to a Ga vacancy or Ga vacancy-O vacancy complex. In addition, CL spectroscopy and depth-resolved CL have demonstrated consistent blue and ultraviolet emissions across the Al content range and a similar suppression of electron concentration on blue and ultraviolet emissions in β-(Al<subscript>x</subscript>Ga<subscript>1−x</subscript>)<subscript>2</subscript>O<subscript>3</subscript> and β-Ga<subscript>2</subscript>O<subscript>3</subscript>. Based on the observed evolution of defects with Al content, the blue band emission is attributed to electron transition in the donor–accepter pair. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00036951
- Volume :
- 124
- Issue :
- 11
- Database :
- Complementary Index
- Journal :
- Applied Physics Letters
- Publication Type :
- Academic Journal
- Accession number :
- 176070256
- Full Text :
- https://doi.org/10.1063/5.0190863