Tunable Rapid Electron Transport in Titanium Oxide Thin Films

TL;DR

This study demonstrates tunable rapid electron transport in titanium oxide thin films, revealing a transition from semiconducting to metallic states and the formation of a Schottky quantum well, enabling novel nanoelectronic device functionalities.

Contribution

We developed a physical conductivity model for multilayer titanium oxide films and showed how electric fields can tune electron transfer and mobility in the quantum well.

Findings

Electron transport switches from semiconducting to metallic with oxidation level.

Electron mobility and concentration in the quantum well can be electrically tuned.

Differential resistivity decreases by two orders with increased electric field.

Abstract

Rapid electron transport in the quantum well triggers many novel physical phenomena and becomes a critical point for the high-speed electronics. Here, we found electrical properties of the titanium oxide changed from semiconducting to metallic as the degree of oxidation decreased and Schottky quantum well was formed at the interface. We take the asymmetry interface electron scattering effect into consideration when studying the electrical transport properties of the multilayer thin films. A novel physical conductivity model for the multilayer thin films was developed. We found electron would be transferred from the low-mobility semiconducting and metallic conductive channels to the high-mobility Schottky quantum well conductive channel with an in-plane applied electric field. Electron concentration and mobility of the forming 2DEG in the Schottky quantum well could be tuned thus the nano-devices exhibited non-linear voltage-current curves. The differential resistivity of the nano-devices could decrease by two orders with increasing electric field at room temperature. Weak electron localization of electrons has been experimentally observed in our nano-devices at low temperature, which further demonstrated the existence of 2DEG in the Schottky quantum well. Our work will provide us new physics about the rapid electron transport in the multilayer thin films, and bring novel functional devices for the modern microelectronic industry.