Piezoelectricity at the Nanoscale: New Methods and Materials

David Wang Auditorium, 3rd floor Dalia Maydan Bldg.
Dr. Yonatan Calahorra

Dr. Yonatan Calahorra

Department of Materials Science and Metallurgy
University of Cambridge
Cambridge, UK

Recent conceptual technological developments, e.g. Internet-of-Things and digital healthcare, drive the need to develop applications such as low- or self-powered sensors, and smart/functional materials to enable them. In this talk, I will offer a fresh point of view to piezoelectricity, focused on nanoscale and non-ceramic materials. Nanoscale electromechanical materials offer advantages compared to bulk due to enhanced surface area and flexibility. Nonetheless, piezoelectric characterization at the nanoscale is challenging due to practical limitations of existing methods and co-existence of different electromechanical effects. I will present atomic force microscopy (AFM) methodologies I developed specifically to overcome existing limitations, and distinguish competing effects. I will show their application to probe piezoelectricity in materials previously inaccessible by standard piezoelectric AFM methods. In particular, correlating internal/crystalline structure and piezoelectric response in self-assembled cellulose nanofibres and III-V semiconductor nanowires. Next, I will present the implementation of nanostructured piezoelectric semiconductors as electromechanical sensors/energy harvesters, and discuss fundamental and practical aspects in achieving efficient electromechanical coupling. These results demonstrate the breadth of effects and functionalities offered by nanoscale electromechanical materials. I will share potential uses and research directions inspired by non-conventional piezoelectric nanomaterials acting as a smart/functional materials infrastructure.