Affiliation:
1. Department of Materials Science and Engineering Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
2. Materials Characterization Center Korea Institute of Materials Science Changwon 51508 Republic of Korea
3. Center of Van der Waals Quantum Solids Institute for Basic Science (IBS) Pohang Pohang 37673 Republic of Korea
4. Department of Semiconductor Engineering Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
Abstract
AbstractThe metal–insulator (MI) transition of vanadium dioxide (VO2) is effectively modulated by oxygen vacancies, which decrease the transition temperature and insulating resistance. Oxygen vacancies in thin films can be driven by oxygen transport using electrochemical potential. This study delves into the role of crystallographic channels in VO2 in facilitating oxygen transport and the subsequent tuning of electrical properties. A model system is designed with two types of VO2 thin films: (100)‐ and (001)‐oriented, where channels align parallel and perpendicular to the surface, respectively. Growing an oxygen‐deficient TiO2 layer on these VO2 films prompted oxygen transport from VO2 to TiO2. Notably, in (001)‐VO2 film, where oxygen ions move along the open channels, the oxygen migration deepens the depleted region beyond that in (100)‐VO2, leading to more pronounced changes in metal‐insulator transition behaviors. The findings emphasize the importance of understanding the intrinsic crystal structure, such as channel pathways, in controlling ionic defects and customizing electrical properties for applications.