Survey of donor dopants reported

Calculated charge-state transition levels for candidate donor dopants shown with respect to the conduction band edge in (AlxGa1-x)2O3 alloys, shown as a function of Al content. All dopants levels cross the band edge at a critical composition in which they lead to localized states, rendering them ineffective dopants.
Calculated charge-state transition levels for candidate donor dopants shown with respect to the conduction band edge in (AlxGa1-x)2O3 alloys, shown as a function of Al content. All dopants levels cross the band edge at a critical composition in which they lead to localized states, rendering them ineffective dopants.

CMI scientists at Lawrence Livermore National Laboratory contributed to this research.

Achievement

Characterization of suitable donor dopants in ultrawide bandgap (Alx,Ga1-x)2O3 (AlGO)

Significance and impact

  • Provides a guide for experimental efforts to make highly conductive, high-Al content AlGO
  • Si dopants found to be best, acting as shallow donors over the entire solubility limit of Al in β-AlGO
  • Suggests common dopants like Sn and Ge will be ineffective in currently studied compositions of ~20-30% Al

Details and next steps

Used electronic structure theory to examine the role of native compensation as a function of composition to identify composition ranges with maximum conductivity

The corresponding Al content and associated bandgap of the critical concentrations for each dopant are summarized in the table.
The corresponding Al content and associated bandgap of the 
critical concentrations for each dopant are summarized in the table.