We have investigated the effect of over oxidized surface layer on the characteristics of metal-insulator transition (MIT) of vanadium dioxide (VO2) films grown by thermal oxidation method. During the oxidation, the over-oxidized V6O13 layer was formed, which increased contact resistance and thus reduced the resistivity ratio before and after MIT. The contact resistivity of the VO2 film with over-oxidized surface layer was in the range 4.2 × 10−2 ∼ 9.4 × 10−4 Ωcm2. Interestingly, the over-oxidized surface layer was removed by simply cooling the film under reduced oxygen pressure. Upon the removal of the over-oxidized layer, the resistivity ratio across MIT increased up to 1.2 × 104. The ratio of contact resistance to sample resistance was small (large) at low (high) temperature.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physics and Astronomy(all)