SAWs are mechanical vibrations travelling along the surface of a material, which resemble micro earthquakes on the surface of a chip. This PhD project exploits super high-frequency (SHF >3 GHz) SAWs for carrier transport and band-structure modulation of epitaxial graphene (epiG) on SiC. The ESR will synthesise epiG and study transport properties under SAW with wavelengths comparable to the carrier mean free path (≤100 nm) aiming at mobility control and possible detection of phonon-mediated superconductivity. Strong SAW fields will be obtained by coupling epiG to phononic crystals. The activities will include:
- epiG synthesis by surface graphitization of SiC
- fabrication of transducer for the generation of SHF SAWSs using nanoimprint lithography (internship at Universiteit Twente, Enschede, NL) and e-beam lithography (internship at Chalmers Technical University, Göteborg, Sweden)
- Raman and magneto-transport spectroscopy studies (internship at University of Leeds, UK) under short-period SAWs
- fabrication and characterisation of phononic crystals on epiG (internship at Queen's University, Canada)
- Theoretical support and training in collaboration with the Universidad Complutense de Madrid and Instituto de Ciencia de Materiales de Madrid (Spain).
Potential applications include acousto-electric switches and attenuators analogues to optical devices (e.g. electron super-collimators and lenses). The multidisciplinary training will include: synthesis of epiG on SiC, characterization techniques (Raman spectroscopy, AFM, Hall measurements), cleanroom techniques (photolithography, nanoimprint lithography, e-beam lithography, etching, sputtering of piezoelectric layers), measurement techniques for SAW devices (interferometry, magnetotransport, spectroscopy), design of phononic-crystals and characterization, as well as theoretical training.