Embedding epitaxial VO 2 film with quality metal-insulator transition to SAW devices

Epitaxial VO 2 films grown by pulsed laser deposition (PLD) method with superior phase transition related switching characteristics are successfully embedded to SAW devices using concept of the “impedance loaded SAW sensor”. A resistance of VO 2 sensor abruptly drops from 0.7 M[Formula: see text] to 90 [Formula: see text] when it is heated above [Formula: see text]65[Formula: see text]C and shows a narrow hysteresis loops when switching. Two designs of SAW devices are examined in which RF signal is reflected back from interdigital transducer (IDT) or a surface acoustic waves (SAW) is transferred through a coupler and the RF response is altered 2 and 3 times correspondingly upon the phase transition in VO 2 . In the proposed devices with external load, a SAW does not propagate via VO 2 film and therefore is not attenuated which is beneficiary for wireless applications. Additionally, a SAW phase shift as great as 50[Formula: see text] is induced to the SAW transferred through the coupler due to the phase transition in VO 2 . The proposed approach may boost the development of remotely controlled autonomous sensors, including those based on VO 2 metamaterials and hybrid plasmonic structures for near IR/middle IR and sub-THz/THz applications.