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.
Bibliographical noteFunding Information:
H. L. Ju and B. S. Mun would like to thank the Basic Science Research Program for support through grants from the National Research Foundation of Korea (NRF) funded by the Korean Government (MOE) ( NRF-2015R1D1A1A01059297 & NRF-2015R1A2A2A01004084 ). B. S. Mun would like to acknowledge support from “GRI (GIST Research Institute)” Project through a grant provided by GIST in 2016.
© 2016 Elsevier B.V.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physics and Astronomy(all)