Programming emissivity on fully integrated VO2 windows

José Figueroa, Yunqi Cao, Tongyu Wang, David Torres, Nelson Sepúlveda*

Department of Electrical and Computer Engineering, Michigan State University, East Lansing, Michigan, 48824

Adv. Mater. Lett., 2018, 9 (6), pp 406-410

DOI: 10.5185/amlett.2018.1848

Publication Date (Web): May 17, 2018

E-mail: nelsons@egr.msu.edu

Abstract


The programmability of emissivity states in a monolithically integrated micro window based on vanadium dioxide (VO2) thin film is demonstrated. The 400  window features a VO2 thin film with integrated electrodes for actuation and sensing. The phase transition was induced by resistive heating, while the electrical resistivity and optical transmittance (for near IR wavelength of 1550 nm) of the VO2 thin film were monitored simultaneously. Abrupt drops in electrical resistance and optical transmittance confirmed the quality of the VO2 thin film. Electronic pulses were used to program emissivity states in the VO2 window. The emissivity programmed state was shown for a specific DC current over imposed with the programming pulse; but any emissivity state that belongs to the minor hysteretic curves can be obtained by choosing different electronic inputs. The fully monolithically integrated device presented here can be used for IR cloaking applications, where different emissivity values can be programmed with electronic pulses.

Keywords

Emissivity, smart materials, vanadium dioxide.

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