Augmentation of thermoelectric performance of VO sub(2) thin films irradiated by 200 MeV Ag super(9+)-ions
Swift Heavy Ion (SHI) irradiation with 200 MeV Ag super(9+)-ion beam at ion fluences of 1E11, 5E11, 1E12, and 5E12 for tuning of electrical transport properties of VO sub(2) thin films fabricated by so-gel technique on alumina substrates has been demonstrated in the present paper. The point defects...
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| Published in: | Radiation physics and chemistry (Oxford, England : 1993) Vol. 123; pp. 55 - 62 |
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| Main Authors: | , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
01-06-2016
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| Subjects: | |
| Online Access: | Get full text |
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| Summary: | Swift Heavy Ion (SHI) irradiation with 200 MeV Ag super(9+)-ion beam at ion fluences of 1E11, 5E11, 1E12, and 5E12 for tuning of electrical transport properties of VO sub(2) thin films fabricated by so-gel technique on alumina substrates has been demonstrated in the present paper. The point defects created by SHI irradiation modulate metal to insulator phase transition temperature, carrier concentration, carrier mobility, electrical conductivity, and Seebeck coefficient of VO sub(2) thin films. The structural properties of the films were characterized by XRD and Raman spectroscopy and crystallite size was found to decrease upon irradiation. The atomic force microscopy revealed that the surface roughness of specimens first decreased and then increased with increasing fluence. Both resistance as well as Seebeck coefficient measurements demonstrated that all the samples exhibit metal-insulator phase transition and the transition temperatures decreases with increasing fluence. Hall effect measurements exhibited that carrier concentration increased continuously with increasing fluence which resulted in an increase of electrical conductivity by several orders of magnitude in the insulating phase. Seebeck coefficient in insulating phase remained almost constant in spite of an increase in the electrical conductivity by several orders of magnitude making SHI irradiation an alternative stratagem for augmentation of thermoelectric performance of the materials. The carrier mobility at room temperature decreased up to the beam fluence of 5E11 and then started increasing whereas Seebeck coefficient in metallic state first increased with increasing ion beam fluence up to 5E11 and thereafter decreased. Variation of these electrical transport parameters has been explained in detail. |
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| Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 content type line 23 ObjectType-Feature-2 |
| ISSN: | 0969-806X |
| DOI: | 10.1016/j.radphyschem.2016.02.020 |