报告题目：Advanced Scanning Probe Microscope and its Application in Transition Metal Oxides
报告人：卢万恒博士 (National University of Singapore)
Scanning probe microscope (SPM) plays an important role in the development of nanoscience and nanotechnology, which refers to a branch of microscopy that allows nanoscale probing the surface structure and also diverse properties, such as mechanical, electrical, magnetic, piezo/ferroelectric, and electrochemical properties. In this presentation, the principle of some scanning probe microscope, including atomic force microscopy (AFM), conductive AFM (c-AFM), electrostatic force microscopy (EFM), Kelvin probe force microscopy (KPFM), and electrochemical strain microscopy (ESM), and their application in materials characterization are introduced. Beyond that, the work, titled as “SPM characterizing the resistive switching properties of binary transition metal oxides (e.g. NiO, TiO2, and VO2)” is analyzed as an example. Resistive switching refers to the resistance change induced by external voltages, which forms the basis of resistance random access memory (RRAM), a promising candidate for next-generation non-volatile memory. As the miniaturization of electronic devices, especially memory devices, resistive switching at the nanoscale is attracting more attention, and in this situation at the nanoscale, some anomalous electrochemical phenomena may initiate and even become significant, for example, an electric field can be applied to a nanoscale volume of material via a conductive probe with a radius of tens of nanometers, and in this case, the strength of the electric field may be extremely high to drive the ionic movement or electrochemical reaction, consequently affecting the resistive switching of materials. Thus, in this example, the application of multiple SPM a powerful tool in investigating the resistive switching at the nanoscale as well as the electrochemical phenomena is viewed, aiming to provide a new insight into the resistive switching of transition metal oxides, and also a full insight into diverse SPM.
Dr. Wanheng Lu obtained her doctoral degree in 2017 from National University of Singapore (NUS), and subsequently, she started working at NUS as a research fellow. Dr. Wanheng Lu’s research primarily focuses on the materials characterization by using advanced scanning probe microscope. In particular, she has conducted SPM characterization of the resistive switching of binary transition metal oxides during her Ph.D. study, and now she is working on SPM studies about nanocomposites with potential in energy generation/conversion, work function-tunable 2D materials, electrification, Li-ion battery materials, and photoactive materials. Till now, Dr. Wanheng Lu has published a number of papers on Journals with a good reputation, for example, Nature Communication, and ACS applied materials and interface.