Reduced viscous damping in high frequency Piezoelectric Resonant Nanochannels for sensing in fluids

This work reports on the demonstration of a new class of high frequency piezoelectric aluminum nitride resonant sensors, dubbed Piezoelectric Resonant Nanochannels (PRNs), for operation in liquid environment with reduced viscous damping. A novel process consisting of 7 lithographic steps was developed to fabricate the PRNs of this work. The new resonant devices operating at high frequencies (278 and 458 MHz) show an unchanged value of the electromechanical coupling, k_t² (about 0.7 and 0.8%), whether the channel is filled with air or a liquid. A quality factor in fluid, Q_f, as high as 464 and 340 is recorded when the 278 MHz PRN is filled with DI-water and 25% glycerol solution, respectively.