Abstract: Industrial VO2 crystal thin films are produced through thermal decomposition method and reduction method with industrial V2O5 as raw material. The suddenly changing properties of VO2 thin films’ resistance were tested. The effects of preparation technological parameters on suddenly changing of VO2 thin films’ resistance and its stability at natural condition were studied. The results show that: 1)The suddenly changing of VO2 thin films’ resistance reaches 2.0~3.4 order of magnitude, and the temperature of its suddenly changing is about 35℃, which is lower 33℃ than that of pure VO2 thin film; 2)the order of magnitude of suddenly changing of the VO2 thin films’ resistance on quartz glass are larger than those on ordinary glass; 3)the order of magnitude of suddenly changing of the VO2 thin films’ resistance by H2 reduction method are larger than those by N2 thermal decomposition method; 4)VO2 thin films can undergo continuous and repeat the M-S phase transition at natural conditions and in short time, decreasing of order of magnitude of suddenly changing is less, and temperature hysteresis of suddenly changing do not nearly vary; 5)under the same conditions the decreasing of order of magnitude of suddenly changing of VO2 thin films’ resistance on quartz glass is less, and its stability is better.
Suddenly changing of resistance and its stability of industrial VO2 thin films
Abstract:
Industrial VO 2 crystal thin films are produced through thermal decomposition method and reduction method with industrial V 2O 5 as raw material. The suddenly changing properties of VO 2 thin films' resistance were tested. The effects of preparation technological parameters on suddenly changing of VO 2 thin films' resistance and its stability at natural condition were studied. The results show that: 1) The suddenly changing of VO 2 thin films' resistance reaches 2.0~3.4 order of magnitude, and the temperature of its suddenly changing is about 35℃, which is lower 33℃ than that of pure VO 2 thin film; 2) the order of magnitude of suddenly changing of the VO 2 thin films' resistance on quartz glass are larger than those on ordinary glass; 3) the order of magnitude of suddenly changing of the VO 2 thin films' resistance by H 2 reduction method are larger than those by N 2 thermal decomposition method; 4) VO 2 thin films can undergo continuous and repeat the M-S phase transition at natural conditions and in short time, decreasing of order of magnitude of suddenly changing is less, and temperature hysteresis of suddenly changing do not nearly vary; 5) under the same conditions the decreasing of order of magnitude of suddenly changing of VO 2 thin films' resistance on quartz glass is less, and its stability is better.
Table 2 Forms of thin film under different thermal decomposition conditions
Thermal decomposition conditions
350 ℃, 8 h; 400 ℃, 5 h
450 ℃, 5~8 h
480 ℃, 3~5 h
520 ℃, 3~5 h
Forms of thin film
From yellowish-brown color to shallow yellow-green, appearance is intact, V2O5 does not volatilize.
From yellowish-brown color to light green, appearance is intact, V2O5 does not volatilize basically.
After 3 h few V2O5 volatilize, after 5 h the most of V2O5 have volatilized, therefore it has been not complete thin films.
After 3 h V2O5 has volatilized in large quantities, after 5 h it has volatilized completely, only a little residues can not volatilize on substrates.
图2 VO2薄膜电阻突变
Fig.2 Suddenly changing of VO2 thin films' resistance
(a) —Ordinary glass as substrate and H2reduction method; (b) —Ordinary glass as substrate and N2thermal decomposition; (c) —Quartz glass as substrate and H2reduction method; (d) —Quartz glass as substrate and N2thermal decomposition method