IMF2017

A new paradigm for piezoelectrically actuated MEMS/NEMS biosensors and energy harvesting devices, impacting quality of life, is based on the integration of dissimilar biocompatible piezoelectric oxide and nanocarbon-based materials. This talk reviews recent R&D performed to integrate lead-free piezoelectric BiFeO₃/SrTiO₃/BFO nanolaminate structures, with superior properties to BFO films, with novel ultananocrystalline diamond (UNCD) films, to develop a new generation of multifunctional MEMS/NEMS actuators and sensors for medical applications. BFO may provide biocompatibility as opposed to lead-based PZT. BFO exhibit remnant polarization P_r and piezoelectric coefficient d₃₃ of comparable to Ti-rich PZT films. However, BFO films exhibit large coercive fields/leakage current, the latter not properly reduced via atomic doping. One part of this talk will focus on reviewing the R&D recently performed on a novel approach to reduce leakage current and increase piezoelectric response of BFO films by producing structured BFO/STO/BFO nanolaminates involving an insulating SrTiO₃ layer. The BFO/STO/BFO nanolaminates exhibit strain-engineered BFO/STO interfaces, providing the mechanism for high piezoelectric deflection/low leakage current (~10^-8 A/cm² -1 V), revealed by systematic HRTEM/PFM studies. The talk will review also R&D that produced new biocompatible UNCD film based MEMS/NEMS structures integrated with piezoelectric films, demonstrating the feasibility of oxide piezoelectric/UNCD integrated MEMS biosensor and energy harvesting devices, the latter via mechanical motion triggered by biting mice heart cells grown on the UNCD film. The integrated biocompatible piezoelectric BFO/STO/BFO nanolaminates/UNCD films provide the bases for a new generation of multifunctional MEMS/NEMS devices for biomedical applications.