Low-cost VO2(M1) thin films synthesized by ultrasonic nebulized spray pyrolysis of an aqueous combustion mixture for IR photodetection

Tadeo, Inyalot Jude and Mukhokosi, Emma P and Krupanidhi, Saluru B and Umarji, ArunM (2019) Low-cost VO2(M1) thin films synthesized by ultrasonic nebulized spray pyrolysis of an aqueous combustion mixture for IR photodetection. In: RSC ADVANCES, 9 (18). pp. 9983-9992.

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Abstract

We report detailed structural, electrical transport and IR photoresponse properties of large area VO2(M1) thin films deposited by a simple cost-effective two-step technique. Phase purity was confirmed by XRD and Raman spectroscopy studies. The high quality of the films was further established by a phase change from low temperature monoclinic phase to high temperature tetragonal rutile phase at 68 degrees C from temperature dependent Raman studies. An optical band gap of 0.75 eV was estimated from UV-visible spectroscopy. FTIR studies showed 60% reflectance change at = 7.7 m from low reflectivity at low temperature to high reflectivity at high temperature in a transition temperature of 68 degrees C. Electrical characterization showed a first order transition of the films with a resistance change of four orders of magnitude and TCR of -3.3% K-1 at 30 degrees C. Hall-effect measurements revealed the n-type nature of VO2 thin films with room temperature Hall mobility, (e) of 0.097 cm(2) V-1 s(-1), conductivity, sigma of 0.102 (-1) cm(-1) and carrier concentration, n(e) = 5.36 x 10(17) cm(-3). In addition, we fabricated a high photoresponsive IR photodetector based on VO2(M1) thin films with excellent stability and reproducibility in ambient conditions using a low-cost method. The VO2(M1) photodetector exhibited high sensitivity, responsivity, quantum efficiency, detectivity and photoconductive gain of 5.18%, 1.54 mA W-1, 0.18%, 3.53 x 10(10) jones and 9.99 x 10(3) respectively upon illumination with a 1064 nm laser at a power density of 200 mW cm(-2) and 10 V bias voltage at room temperature.

Item Type:	Journal Article
Publication:	RSC ADVANCES
Publisher:	ROYAL SOC CHEMISTRY
Additional Information:	Copyright for this article belongs to ROYAL SOC CHEMISTRY
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	27 May 2019 06:19
Last Modified:	27 May 2019 06:19
URI:	http://eprints.iisc.ac.in/id/eprint/62750

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