Rutile-type GexSn1−xO2 alloy layers lattice-matched to TiO2 substrates for device applications

We report the characterization and application of mist-CVD-grown rutile-structured GexSn1−xO2 (x = ∼0.53) films lattice-matched to isostructural TiO2(001) substrates. The grown surface was flat throughout the growth owing to the lattice-matching epitaxy. Additionally, the film was single-crystalline without misoriented domains and TEM-detectable threading dislocations due to the coherent heterointerface. Using the Ge0.49Sn0.51O2 film with a carrier density of 7.8 × 1018 cm−3 and a mobility of 24 cm2V−1s−1, lateral Schottky barrier diodes were fabricated with Pt anodes and Ti/Au cathodes. The diodes exhibited rectifying properties with a rectification ratio of 8.2 × 104 at ±5 V, showing the potential of GexSn1-xO2 as a practical semiconductor.