Origin of p-type conductivity in LiGa5O8 thin films

Determine the definitive microscopic origin of p-type conductivity in mist-CVD-grown LiGa5O8 thin films, including the roles of Li deficiency, β-Ga2O3 secondary-phase formation, and interfacial charge transfer.

Background

The paper investigates why some mist-CVD-grown LiGa5O8 thin films exhibit room-temperature p-type conductivity while others are insulating. Although the reported measurements correlate p-type behavior with Li-deficient compositions and the presence of a secondary β-Ga2O3 phase, first-principles calculations indicate that native acceptors in pure LiGa5O8 are too deep to account straightforwardly for the observed hole concentrations.

The authors therefore propose that a type-II LiGa5O8/β-Ga2O3 interface enables electrons from the β-Ga2O3 valence band to occupy Li-vacancy- and Li-on-Ga-related acceptor states in LiGa5O8, leaving holes in β-Ga2O3. This mechanism remains a proposed explanation rather than a definitive determination of the origin of the conductivity.