Observation of in situ oxidation dynamics of vanadium thin film with ambient pressure X-ray photoemission spectroscopy

The evolution of oxidation/reduction states of vanadium oxide thin film was monitored in situ as a function of oxygen pressure and temperature via ambient pressure X-ray photoemission spectroscopy. Spectra analysis showed that VO₂ can be grown at a relatively low temperature, T ∼ 523 K, and that V₂O₅ oxide develops rapidly at elevated oxygen pressure. Raman spectroscopy was applied to confirm the formation of VO₂ oxide inside of the film. In addition, the temperature-dependent resistivity measurement on the grown thin film, e.g., 20 nm exhibited a desirable metal-insulator transition of VO₂ with a resistivity change of ∼1.5 × 10³ times at 349.3 K, displaying typical characteristics of thick VO₂ film, e.g., 100 nm thick. Our results not only provide important spectroscopic information for the fabrication of vanadium oxides, but also show that high quality VO₂ films can be formed at relatively low temperature, which is highly critical for engineering oxide film for heat-sensitive electronic devices.