Dr. Filippo GiubileoSenior Researcher
Institute for Superconductors, Innovative Materials and Devices (SPIN)
Italian National Research Council (CNR)
Speech Title: Field Emission characterization of two-dimensional nanosheets
Abstract: Field emission (FE) phenomenon is exploited to develop cold electron sources for flat panel displays, electron microscopy, as well as X-ray sources. The application of a high electric field can favour the emission of electrons from a metallic or semiconducting surface by tunnelling effect through the vacuum barrier. Indeed, the intense electric field causes a reduction of the potential barrier at the interface between the emitting surface and the vacuum. Moreover, nanostructured emitters can profit of an important field enhancement at the edge of the emitters, due to their aspect ratio. Therefore, several kind of nanostructures are investigated as FE devices. In particular, two-dimensional transition metal dichalcogenides (TMDs) have sharp edges that favour the field enhancement and consequently the emission of electrons at a relatively low turn-on field. In this talk, we will discuss the field emission properties of TMDs (such as MoS2, PdSe2 and WSe2). We report detailed experimental characterization performed by using a tip-shaped anode inside a scanning electron microscope in order to precisely tune the cathode-anode separation distance and obtain high field with relatively low voltages. We also show that by having the two-dimensional TMD nanosheets on a Si/SiO2 substrate, the FE current can be modulated by the back-gate voltage (where the Si is used as gate), demonstrating the possibility to develop a TMD-based vertical field emission transistor.
Keywords: Field emission, Transition metal dichalcogenides, two-dimensional, nanosheets, field enhancement factor, Fowler-Nordheim theory.
Biography: Filippo Giubileo currently works as Senior Researcher at the Institute for Superconductors, Innovative Materials and Devices (SPIN) of the Italian National Research Council (CNR), since 2004. He has the National Scientific Qualification as Full Professor in Experimental Condensed Matter Physics. He has been member of the scientific evaluation panel for the Flag-Era Joint Transnational call on graphene basic research. His research activity deals with electrical properties of 1D and 2D materials and their application as field effect transistors, photodetectors, chemical sensors, field emitters. FG is listed in the World Top 2% Scientist classification by PlosBiology. He has published more than 100 papers in peer-reviewed journals. He was Chair-Organiser for 6 international conferences (ISMN08, SM-2010, S4E-2014, GM-2016, TTN-2018, NANO M&D-2019). He serves as member of editorial board for several international journals (Nanomaterials, Nano Express, Journal of Nanomaterials, Chemosensors).