Hydrogen incorporation induced the octahedral symmetry variation in VO2 films
| Autor: | Sungkyun Park, Yooseok Kim, Ik-Jae Lee, Jiwoong Kim, Hyung-Joong Yun, Dooyong Lee, Jouhahn Lee, Hyegyeong Kim |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Materials science
Hydrogen Annealing (metallurgy) General Physics and Astronomy chemistry.chemical_element 02 engineering and technology Surfaces and Interfaces General Chemistry Sputter deposition 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Surfaces Coatings and Films Crystallography symbols.namesake chemistry Rutile Sputtering X-ray crystallography symbols 0210 nano-technology Raman spectroscopy Monoclinic crystal system |
| Zdroj: | Applied Surface Science. 396:36-40 |
| ISSN: | 0169-4332 |
| DOI: | 10.1016/j.apsusc.2016.11.047 |
| Popis: | This study examined the microscopic aspects of macroscopic physical property variations of hydrogen annealed VO2 films, deposited on Al2O3(0001) substrates by RF magnetron sputtering. The temperature-dependent electrical resistivity showed that the as-grown film exhibited a metal-insulator-transition (MIT) at 55.20 °C and 49.26 °C during heating and cooling, respectively. On the other hand, no MIT was observed for the film annealed under a hydrogen environment. Spectroscopic measurements during the in-situ hydrogenation process showed that hydrogen annealing (∼0.3 mbar, up to 300 °C) promoted the V3+ state above 100 °C. Raman spectroscopy and X-ray diffraction confirmed that the as-grown film changed from a monoclinic to rutile structure during hydrogen annealing. In addition, the shift of the (020) diffraction peak position of the hydrogen-annealed film to a lower angle compare to that of the known rutile VO2 film was attributed to the expansion of the unit cell. In addition, local structure analysis showed that an increase in octahedral symmetry after hydrogen annealing is one of the main explanations for the metallic characteristics of the hydrogen-annealed film. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect