Electrical and Optical Characteristics of Vanadium Doped Amorphous Silicon Dioxide Films Prepared by CVD

Previous experiments on pure and vanadium (V) doped amorphous silicon dioxide (a-SiO₂) films prepared by r.f. sputtering have shown that both the V-doped and undoped films can be switched reproducibly between two stable states of widely differing conductivity by field stressing the films1,2. Similar experiments using chromium, colbalt or titanium doping have also resulted in significant changes in the electrical properties of the oxide, but in these cases the material was less stable, even when annealed, with instabilities present at low to moderate fields. The behaviour of such materials is of great interest from both pure and applied aspects, but greater control over preparation is desirable. In the present paper we report the electrical and optical properties of V-doped a-SiO₂ films prepared by CVD and compare them with the previous results on sputtered films.