The effect of vacuum preheating on the structure, electric, and optical properties of W-doped VO2 films prepared from thermal oxidation

The effect of vacuum preheating on the structure, electric, and optical properties of the thermally oxidized W-doped VO2 films was studied. The results show that the film crystalline orientation and the inhomogeneous distribution of W increase after preheating. It was found that preheating at 700 degrees C and 800 degrees C reduces the metal-insulator transition (MIT) hysteresis because of the preferable orientation of the film along the (011) direction. The film preheated at 900 degrees C exhibits an undoped-like MIT due to a great increase in the inhomogeneous distribution of W. Preheating can affect the apparent activation energy of the cool-state resistances and increase the cool-state IR transmittances. By means of the Lorentz-Drude model, the conductance electron density (n (c)) and energy band gaps (E (g)) were obtained and discussed. It was shown that preheating can decrease the cool-state n (c) and affect the E (g), indicating that the electronic band structure is changed by W doping.

Automated summary

The effect of vacuum preheating on the structure, electric, and optical properties of W-doped VO2 films was investigated. Preheating increased the film crystalline orientation and inhomogeneous distribution of W. Preheating at 700°C and 800°C reduced the metal-insulator transition hysteresis due to the preferred film orientation along the (011) direction. At 900°C, the preheated film exhibited an undoped-like metal-insulator transition due to an increase in the inhomogeneous distribution of W. Preheating affected the apparent activation energy of the cool-state resistances and increased the cool-state IR transmittances. Using the Lorentz-Drude model, the conductance electron density and energy band gaps were obtained and discussed. Preheating decreased the cool-state electron density and affected the energy band gaps, indicating a change in the electronic band structure due to W doping.