Thermochromic VO2 thin films on ITO-coated glass substrates for broadband high absorption at infra-red frequencies

Rajeswaran, Bharathi and Pradhan, Jitendra K and Ramakrishna, S. Anantha and Umarji, Arun M (2017) Thermochromic VO2 thin films on ITO-coated glass substrates for broadband high absorption at infra-red frequencies. In: JOURNAL OF APPLIED PHYSICS, 122 (16).

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Abstract

Thin films of vanadium dioxide (VO2) are deposited on indium tin oxide (ITO), stainless steel (SS), and glass substrates using chemical vapour deposition. X-ray diffraction and Raman spectroscopy measurements confirmed the single phase nature of the VO2, which showed a phase transition from a low conducting state at low temperature(<68 degrees C) to a high conducting state at high temperature (>68 degrees C). This was confirmed by electrical conductance and infra-red reflectance measurements. X-ray photoelectron spectroscopy was used to measure the charge states of vanadium species. The optical constants of VO2 were determined using visible and near-infra red(NIR) reflectivity and show that the VO2 film on ITO has a lowered plasma frequency compared with VO2 on glass substrates. The thin films of VO2 enable a broadband of ultra-high absorption at mid-wave infra-red frequencies due to a Fabry-Perot (F-P) like resonance due to the dielectric properties of ITO, SS, or glass. The tunability of this absorption band via VO2 thickness and the switchability by temperature makes the system attractive for absorptive coatings with controllable emissivity. Published by AIP Publishing.

Item Type:	Journal Article
Publication:	JOURNAL OF APPLIED PHYSICS
Additional Information:	Copy right for this article belongs to the AMER INST PHYSICS, 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	22 Nov 2017 06:36
Last Modified:	22 Nov 2017 06:36
URI:	http://eprints.iisc.ac.in/id/eprint/58312

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