Resistance noise at the metal-insulator transition in thermochromic VO2 films
2015 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 117, no 2, 1-7 p., 025303Article in journal (Refereed) Published
Thermochromic VO2 films were prepared by reactive DC magnetron sputtering onto heated sapphire substrates and were used to make 100-nm-thick samples that were 10 lm wide and 100 lm long. The resistance of these samples changed by a factor similar to 2000 in the 50<T-s<70 degrees C range of temperature T-s around the "critical" temperature T-c between a low-temperature semiconducting phase and a high-temperature metallic-like phase of VO2. Power density spectra S(f) were extracted for resistance noise around T-c and demonstrated unambiguous 1/f behavior. Data on S(10 Hz)/R-s(2) scaled as R-s(x), where R-s is sample resistance; the noise exponent x was -2.6 for T-s< T-c and +2.6 for T-s>T-c. These exponents can be reconciled with the Pennetta-Trefan-Reggiani theory [Pennetta et al., Phys. Rev. Lett. 85, 5238 (2000)] for lattice percolation with switching disorder ensuing from random defect generation and healing in steady state. Our work hence highlights the dynamic features of the percolating semiconducting and metallic-like regions around T-c in thermochromic VO2 films. (C) 2015 AIP Publishing LLC.
Place, publisher, year, edition, pages
2015. Vol. 117, no 2, 1-7 p., 025303
Other Physics Topics Engineering and Technology
Research subject Engineering Science with specialization in Solid State Physics
IdentifiersURN: urn:nbn:se:uu:diva-245367DOI: 10.1063/1.4905739ISI: 000348129300064OAI: oai:DiVA.org:uu-245367DiVA: diva2:791169