Abstract
Thin films of thermochromic
VO
2
,
V
1
−
x
W
x
O
2
and
V
1
−
x
−
y
W
x
Ti
y
O
2
(
x
=
0.014
, and
y
=
0.12
) were synthesized onto quartz substrates using a reactive pulsed laser deposition technique. The films were then characterized by x-ray diffraction and x-ray photoelectron spectroscopy. The
W
and
Ti
dopant effects on the semiconductor-to-metal phase transition of
VO
2
were investigated by measuring the temperature dependence of their electrical resistivity and their infrared transmittance. Remarkably strong effects of
Ti
-
W
codoping were observed on both the optical and electrical properties of
V
1
−
x
−
y
W
x
Ti
y
O
2
films. The IR transmittance was improved, while the transition temperature could be varied from
36
°
C
for W-doped
VO
2
film to
60
°
C
for
Ti
-
W
codoped
VO
2
film. In addition, at room temperature, a higher temperature coefficient of resistance of
5.12
%
∕
°
C
is achieved. Finally, both optical and electrical hysteresis are completely suppressed by
Ti
-
W
codoping the
VO
2
films.