Multimode characteristics in mechanically-coupled silicon carbide (SiC) nanowire array resonators

We report on the measurements and modeling of mechanically-coupled arrays of very thin silicon carbide nanowire (SiC NW) nanomechanical resonators. The exceptional mechanical properties and attractive optical properties of SiC make it highly interesting for resonant nanoelectromechanical systems (NEMS), with resonant modes operating at high frequencies that can be exploited for resonance-based signal processing and sensing applications. In this work, we demonstrate arrays consisting of SiC NWs as narrow as 50nm, patterned by electron beam lithography and focused ion beam, on ~50-500nm SiC thin epitaxial layers and polycrystalline layers. We investigate the multimode resonances in mechanically coupled arrays. We show that by controlling the undercut ledges of suspended SiC NW arrays, we can tune the strength of mechanical coupling in such arrays and engineer their multimode resonance characteristics.