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Kar-Narayan Lab



We employ electromechanical (piezoresponse), mechanical (quantitative nanomechanical mapping) and electrical (Kelvin-probe) force microscopy to examine basic properties of various piezoelectric materials at the nanoscale, motivated by the desire to improve mechanical energy harvesting efficiency, and mechanical sensing. Most of the work is done using piezoresponse force microscopy (PFM), a scanning probe microscopy mode where the microscope picks-up the mechanical response resulting from an applied voltage by the scanning tip. Since PFM is a contact-mode method, nanoscale and soft materials are extremely challenging as test subjects. Therefore, we are developing a non-destructive method to perform PFM on such samples. Our techniques are applicable to a wide range of novel piezoelectric nanomaterials such as nanowires of piezoelectric polymers and III-V semiconducting materials.