Vanadium dioxide (VO2) is a correlated electron material that exhibits a first-order metal-insulator phase transition (MIT) which is accompanied by a structural transition from a high-temperature rutile phase to a low-temperature monoclinic phase. The abrupt change in the resistivity over several orders of magnitude and the large changes in optical properties makes this material of considerable interest for fundamental reasons as well as for applications in sensors and optics.
Oxide multilayer heteroepitaxy combining Mott-insulator vanadium dioxide (VO2) films and functional conducting/ferroelectric/dielectric films open new opportunities
in creating functional devices with applicability in the field of non-volatile memories for neuromorphic devices due to their sub-nanosecond transition timescale and electrical read-out scheme. The growth of high quality VO2 films is challenging due to the necessity of precise control of the vanadium cation valence state. In this study we report on electrical and structural properties of VO2 thin films deposited on various single crystal oxide substrates commonly used in oxide electronics and on PZT/SRO ferroelectric heterostructers. Thus, SrTiO3(100), SrTiO3(100) with PZT/SrRuO3 template layers, Si(100) substrate with a SrTiO3 template layer, NdGaO3 (110), and PZT/ SrRuO3 template on GdScO3 (110), MgO(100) and PMN-PT(001) were used in combination with VO2 films. The structural characteristics of the deposited VO2 films were evaluated by X-ray diffraction and Raman scattering spectroscopy. Electrical measurements show a change in resistance of the VO2 across MIT ranging from 100 to 10000 times in all investigated substrates/films combinations.