Vanadium dioxide films with nano-structured grains have been prepared by RF-
sputtering followed by thermal annealing in low oxygen pressure. The submicro-structured
crystalline grains with the size of 200 to 250 nm were revealed by FE-SEM micrographs. XRD
analysis proves the monoclinic lattice of the VO2 crystalline structure and the size of the grains
determined from XRD also consists of about 200 nm. The temperature of the semicoductor-to-
metal phase transition (SMPT) of the films was found at tc = 64 o
C. At temperatures higher than tc
the resistance of the films decreased three orders in magnitude, and the transmittance at l = 1550
nm lowered from 55% to a value as low as 30%. From these thermochromic properties of VO2
films one can suggest a practical application in production of thermo-optical sensors that can be
used for monitoring temperature change in petrol and/or toxic chemical storages.
