Thin Film Stabilization of Different VO₂Polymorphs

Abstract

In recent years, VO2 has emerged as a popular candidate among the scientific community across the globe owing to its unique technological and fundamental aspects. VO2 can exist in several polymorphs (such as: A, B, C, D, M1, M2, M3, P, R and T) which offer a broad spectrum of functionalities suitable for numerous potential applications likewise smart windows, switching devices, memory materials, battery materials and so on. Each phase of VO2 has specific physical and chemical properties. The device realization based on specific functionality call for stabilization of good quality single phase VO2 thin films of desired polymorphs. Hence, the control on the growth of different VO2 polymorphs in thin film form is very crucial. Different polymorphs of VO2 can be stabilized by selecting the growth route, growth parameters and type of substrate etc. In this chapter, we present an overview of stabilization of the different phases of VO2 in the thin film form and the identification of these phases mainly by X-ray diffraction and Raman spectroscopy techniques.

Fabrication and Properties of Epitaxial VO2 Thin Film on m-Al2O3 Substrate

“…This is the reason why the researchers have been continuously striving to determine the most viable and optimized method for synthesizing high-quality thin films of VO 2 since the phase transition was first observed in this material. The synthesis of phase-controlled stochiometric VO 2 thin films is slightly tricky as a small variation in the oxygen content can lead to several other compounds of vanadium oxide [12]. Moreover, VO 2 itself can exist in several polymorphs [12].…”

“…The synthesis of phase-controlled stochiometric VO 2 thin films is slightly tricky as a small variation in the oxygen content can lead to several other compounds of vanadium oxide [12]. Moreover, VO 2 itself can exist in several polymorphs [12]. So, the phase-specific growth of VO 2 thin film with the desired orientation is challenging.…”

“…The epitaxial growth of VO 2 thin films is desired to realize the single crystal-like properties for device applications. Until now, researchers have widely studied the epitaxial growth of VO 2 thin films mainly on substrates such as c-Al 2 O 3 and TiO 2 , but studies focused on the epitaxial growth of VO 2 films on m-Al 2 O 3 substrates are limited [12][13][14][15]. This warrants the study of the fabrication and comprehensive characterization of epitaxial VO 2 thin film prepared on other substrates to achieve the desired orientation and/or properties.…”