Fabrication and FUV Spectroscopic Measurement of Orthorhombic MgGeO3 Thin Films

ABO3 is a typical chemical formula shared by various functional oxides. ABO3 oxides containing Ge at the B site are expected to exhibit transparent semiconducting properties due to the combination of wide bandgap and high mobility, as well as various functionalities arising from their crystal structures. In this study, we have attempted to grow MgGeO3 thin films using the sputtering method and investigate their stable crystal structure and fundamental physical properties in the thin-film form. By re-growth using a thin seed layer and high-temperature annealing, we achieved the a-axis-oriented growth of orthorhombic MgGeO3 thin films. UV-VIS and FUV spectroscopy revealed high transparency in the visible region and a wide bandgap of approximately 6 eV.