Rutile-type Ge x Sn1−x O2 alloy layers lattice-matched to TiO2 substrates for device applications

Abstract

We report the characterization and application of mist-CVD-grown rutile-structured Ge _x Sn _1− _x O _2 ( x = ∼ 0.53) films lattice-matched to isostructural TiO _2 (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 Ge _0.49 Sn _0.51 O _2 film with a carrier density of 7.8 × 10 ^18 cm ^−3 and a mobility of 24 cm ^2 V ^−1 s ^−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 × 10 ^4 at ±5 V, showing the potential of Ge _x Sn _1- _x O _2 as a practical semiconductor.