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Abstract The characteristic metal–insulator phase transition (MIT) in vanadium dioxide results in nonlinear electrical transport behavior, allowing VO2devices to imitate the complex functions of neurological behavior. Chemical doping is an established method for varying the properties of the MIT, and interstitial dopant boron has been shown to generate a unique dynamic relaxation effect in individual B‐VO2particles. This paper describes the first demonstration of an electrically stimulated B‐VO2proto‐device which manifests a time‐dependent critical transformation temperature and switching voltage derived from the coupling of dopant diffusion dynamics and the metal–insulator transition of VO2. During quasi‐steady current‐driven transitions, the electrical responses of B‐VO2proto‐devices show a step‐by‐step progression through the phase transformation, evidencing domain transformations within individual particles. The dynamic relaxation effect is shown to increase the critical switching voltage by up to 41% (ΔVcrit =0.13 V) and also to increase the resistivity of the M1 phase of B‐VO2by 14%, imbuing a memristive response derived from intrinsic material properties. These observations demonstrate the dynamic relaxation effect in B‐VO2proto‐devices whose electrical transport responses can be adjusted by electronic phase transitions triggered by temperature but also by time as a result of intrinsic dynamics of interstitial dopants.
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Control of Water Adsorption via Electrically Doped Graphene: Effect of Fermi Level on Uptake and H 2 O Orientation
Abstract The interaction of graphene with water molecules under an applied electric field is not thoroughly understood, yet this interaction is important to many thermal, fluidic, and electrical applications of graphene. In this work, the effect of electrical doping of graphene on water adsorption is studied through adsorption isotherms and current–voltage (IV) characterizations as a function of the Fermi level. The water adsorption onto graphene increases by ≈15% and the doping levels increase by a factor of three with a gate‐to‐graphene voltage of +20 or −20 V compared to 0 V for sub‐monolayer adsorption. This change in uptake is attributed to the increase in density of state of graphene upon electrical‐doping, which changes the Coulombic and van der Waals interactions. The water adsorption onto graphene is either n‐ or p‐doping depending on the applied gate‐to‐graphene voltage. The ambi‐doping nature of water onto graphene is due to the polar nature of water molecules, so the doping depends on the orientation of the water molecules.
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- Award ID(s):
- 1846157
- PAR ID:
- 10449537
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Interfaces
- Volume:
- 8
- Issue:
- 18
- ISSN:
- 2196-7350
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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