Seminars Archive

Thin Films and Nanostructures of Vanadium Dioxide for Reconfigurable Microwave Devices

Abstract
Thales aims to develop electronic and optronic systems for observation, recognition and guidance based on the use of the electromagnetic spectrum from optical to radiofrequency waves. Future such systems will have to achieve autonomous and self-reconfigurable operations, for real-time and efficient self-optimization of their performances. Circuit tunability and reconfigurability are essential to satisfy most of radar / sensing / surveillance system requirements, both for civilian and military applications. In order to achieve reconfigurability there is a strong need to investigate new frequency and wavelength tunable materials whose physical properties can be modified using external commands (e.g. electric field, pressure, mechanical stress, photon absorption). Metal–Insulator phase Transition (MIT) materials such as Vanadium dioxide (VO2) have outstanding potential for future ultra-fast electronics and optics. The electronic transition from semiconductor to metal can be either optically or electrically switched on and off at a timescale down to picosecond and can be used for ultrafast switching devices. Thales plans to use such materials (VO2 but also Rare-Earth Nickelates depending on the temperature range of interest) for manufacturing RF switches to be integrated in Single-Pole-X-Thru (SPXT), phase-shifters devices and then Antenna. However there are many other potential applications of such materials. Especially it is now considered as one way to be investigated for beyond CMOS. A great deal of effort is done today to control the crystalline quality of epitaxially grown thin layers of these materials and thus control their physical properties. A review on the synthesis of VO2 epitaxial thin films and nanostructures will be presented along with their application for RF devices and some other examples of applications will be given.