Abstract
Vanadium oxide (VO
2
) is considered a Peierls–Mott insulator with a metal–insulator transition (MIT) at T
c
= 68° C. The tuning of MIT parameters is a crucial point to use VO
2
within thermoelectric, electrochromic, or thermochromic applications. In this study, the effect of oxygen deficiencies, strain engineering, and metal tungsten doping are combined to tune the MIT with a low phase transition of 20 °C in the air without capsulation. Narrow hysteresis phase transition devices based on multilayer VO
2
, WO
3
, Mo
0.2
W
0.8
O
3,
and/or MoO
3
oxide thin films deposited through a high vacuum sputtering are investigated. The deposited films are structurally, chemically, electrically, and optically characterized. Different conductivity behaviour was observed, with the highest value towards VO
1.75
/WO
2.94
and the lowest VO
1.75
on FTO glass. VO
1.75
/WO
2.94
showed a narrow hysteresis curve with a single-phase transition. Thanks to the role of oxygen vacancies, the MIT temperature decreased to 35 °C, while the lowest value (T
c
= 20 °C) was reached with Mo
0.2
W
0.8
O
3
/VO
2
/MoO
3
structure. In this former sample, Mo
0.2
W
0.8
O
3
was used for the first time as an anti-reflective and anti-oxidative layer. The results showed that the MoO
3
bottom layer is more suitable than WO
3
to enhance the electrical properties of VO
2
thin films. This work is applied to fast phase transition devices.