Localized phase transition of TiO2 thin films induced by sub-bandgap laser irradiation
| Autor: | Yi Gu, Violet M. Poole, John Igo, Syeed E. Ahmed, Matthew D. McCluskey |
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| Rok vydání: | 2021 |
| Předmět: |
Phase transition
Anatase Materials science Analytical chemistry Surfaces and Interfaces Condensed Matter Physics Surfaces Coatings and Films Amorphous solid Crystal Condensed Matter::Materials Science symbols.namesake chemistry.chemical_compound chemistry Rutile Phase (matter) Titanium dioxide symbols Raman spectroscopy |
| Zdroj: | Journal of Vacuum Science & Technology A. 39:053402 |
| ISSN: | 1520-8559 0734-2101 |
| Popis: | The ability to define the crystal phase of oxide semiconductors could benefit transparent electronics and catalysis. In this paper, laser-induced localized phase transitions of titanium dioxide (TiO2) thin films are reported. Irradiation was performed with a 532 nm continuous wave laser. Raman spectroscopy and micro-Raman mapping were used to identify the phase transformations. A Raman map of the anatase Eg mode (144 cm−1) and rutile Ag mode (608 cm−1) revealed the formation of crystalline microstructures due to the laser treatment. Laser irradiation under vacuum results in an anatase-to-rutile phase transition. Irradiating the rutile region in air changes the crystal structure back to anatase, despite the thermodynamic stability of rutile. The results suggest that irradiated photons are absorbed by defects, resulting in localized electronic excitation that leads to a mixture of amorphous and crystalline regions. The phase of the crystalline regions depends strongly on the ambient conditions (vacuum versus air). |
| Databáze: | OpenAIRE |
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