Investigation of VO2 directly deposited on a glass substrate using RF sputtering for a smart window

Herein, a VO2 thin film was directly deposited on soda lime glass by reactive RF sputtering to investigate its potential application in realizing smart windows. The VO2 crystal structure is susceptible to oxygen density; hence, to decrease the sensitivity, we fabricated the VO2 thin film by increasing the RF sputtering power, rather than increasing growth temperature. The orientation of VO2 was changed from (011) to (100) by increasing the RF power from 100 to 180 W. This phenomenon can be explained by the enthalpy compensation and strain effect. This thin film clearly shows the thermochromic characteristic as a drastic variation in the infrared radiation at different temperatures based on the intrinsic transition property of VO2. The directly developed VO2 thin film with high RF power sputtered onto the glass substrate herein can be recommended as a simple and cheap method to add the self-temperature control function to smart windows.