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

Abstract

In this study, a VO2 thin film was directly deposited on a soda-lime glass by reactive RF sputtering to investigate its potential application in smart windows. The VO2 crystal structure is susceptible to changes in the oxygen density; to decrease this sensitivity, we fabricated a VO2 thin film by increasing the RF sputtering power, rather than increasing the 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 using the enthalpy compensation and strain effect. The thin film clearly shows thermochromic characteristics in terms of drastic variation in infrared radiation at different temperatures based on the intrinsic transition property of VO2. Direct deposition of VO2 thin film on a glass substrate using the high RF power sputtering method proposed in this study is recommended as a simple and low-cost method to add a self-temperature control function to smart windows.