Transition metal oxides (TMOs) are among the most fascinating materials studied in solid-state physics, having a great variety of structural, chemical, and transport properties. These materials when prepared in the form of thin films allow the development of new systems with unique features, particularly appealing for numerous technological applications. For instance, VO2 shows an insulator-to-metal transition (IMT) at 340 K with a 4-order magnitude jump in resistivity, which can be modulated through film thickness, light, pressure, and electric field.
This research aims to prepare and study different types of TMOs films (MoO3, WO3, VO2, V2O5, SnO, and SnO2), both to develop and expand the scientific knowledge on TMOs materials and to study the role of transition oxide films in technological applications like protective coating for acceleration cavity in particle physics, IMT and plasmonics.
Although some of these materials are well known and studied, their great variety of chemical-physical states and in general of the properties they possess make them continuous sources of discoveries and innovations.
In particular, the application of protective films for accelerating cavities is of considerable interest for future C-band, W-band, and X-band particle accelerators as it would allow the size reduction increasing the gradient field while maintaining the same performances. These coatings would decrease the breakdown phenomena (discharges) inside the cavities and the emission of electrons (field emission) from the surface thanks to their high work function, without however affecting the quality factor of the cavities.
The sensing of VOCs and organic gaseous compounds, in general, is a rapidly expanding field of research given the urgent need for sensors that allow to measure and distinguish various molecular compounds that are harmful to humans and the environment. The electrical and optical properties of TMOs films are strongly influenced by the presence of molecular compounds on their surface, making them perfect candidates for sensing.
Also, we will combine the metamaterial ability to manipulate the behavior of EM radiation, with the use of TMOs with phase transitions as WO3 and VO2, for the development of fast and selective optical devices. Specific control of the oxides functionalities (critical temperature, phase coexistence, resistivity jumping at the transition, etc.) can be achieved by chemical co-doping and/or applied DC field. Moreover, we will develop specific growing techniques on patterned substrates in order to engineer the final metamaterials.