Atomic-scale characterization of structural and electronic properties of Hf doped β-Ga2O3
Abstract
In this Letter, we investigate the atomic and electronic structure of a Hf-doped beta-gallium oxide (β-Ga2O3) single crystal using high resolution scanning transmission electron microscopy imaging and electron energy loss spectroscopy. Ultraviolet-visible (UV-Vis)-near-infrared absorption measurements and density functional theory calculations are performed to further connect the nanoscale observation to the macroscale properties arising from the atomic structure. The Hf-doped sample was grown from the melt with a nominal Hf concentration of 0.5 at. %. We show that the Hf dopants prefer to occupy octahedral over tetrahedral sites by 0.68 eV and have some resistance to form precipitates due to a repulsive interaction of 0.17 eV between Hf atoms on neighboring sites. Also, the presence of Hf atoms on either tetrahedral or octahedral sites do not significantly affect the crystal structure of β-Ga2O3. Finally, the bandgap values of the Hf doped β-Ga2O3 obtained by electron energy loss spectroscopy and UV-Vis-spectroscopy were Eg = 4.83 ± 0.1 and 4.75 ± 0.02 eV, respectively, similar to the values reported for unintentionally doped β-Ga2O3 crystals. All these results make Hf an excellent dopant candidate for β-Ga2O3.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 25, 2021
- Source ID
- 10.1063/5.0062739
Entities
People
- Adrian Chmielewski
- Jani Jesenovec
- John S. McCloy
- Kelvin G Lynn
- Muad Saleh
- Nasim Alem
- Wolfgang Windl
- Ziling Deng
Organizations
- Air Force Office of Scientific Research
- Ohio State University
- Pennsylvania State University
- Washington State University