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Title: Surface charge sensing by altering the phase transition in VO{sub 2}

Detection of surface charges has various applications in medicine, electronics, biotechnology, etc. The source of surface charge induction may range from simple charge-polarized molecules like water to complicated proteins. It was recently discovered that surface charge accumulation can alter the temperature at which VO{sub 2} undergoes a Mott transition. Here, we deposited polar molecules onto the surface of two-terminal thin-film VO{sub 2} lateral devices and monitored the joule-heating-driven Mott transition, or conductance switching. We observed that the power required to induce the conductance switching reduced upon treatment with polar molecules and, using in-situ blackbody-emission direct measurement of local temperature, we show that this reduction in power was accompanied by reduction in the Mott transition temperature. Further evidence suggested that this effect has specificity to the nature of the species used to induce surface charges. Using x-ray absorption spectroscopy, we also show that there is no detectable change in oxidation state of vanadium or structural phase in the bulk of the 40 nm VO{sub 2} thin-film even as the phase transition temperature is reduced by up to 20 K by the polar molecules. The ability to alter the phase transition parameters by depositing polar molecules suggests a potential application in sensing surface chargesmore » of different origins and this set of results also highlights interesting aspects of the phase transition in VO{sub 2}.« less
Authors:
;  [1] ;  [1] ;  [2] ;  [3]
  1. Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)
  2. (United States)
  3. Stanford Genome Technology Center, 855 California Ave., Palo Alto, California 94304 (United States)
Publication Date:
OSTI Identifier:
22314678
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 7; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION SPECTROSCOPY; DEPOSITS; EMISSION; JOULE HEATING; MOLECULES; PHASE TRANSFORMATIONS; PROTEINS; REDUCTION; SURFACES; THIN FILMS; TRANSITION TEMPERATURE; VANADIUM OXIDES; WATER; X-RAY SPECTROSCOPY