Title: Optoelectronics and Electromechanics of Two Dimensional Materials

Speaker: Dr. Basant Chitara, Ben Gurion University, Israel

Abstract: Two dimensional (2D) materials offering ultra-thinness at the atomistic scale, high electron mobility, tunable bandgap and high mechanical strength, are potential candidates for next-generation electronic devices. These materials provide complete tool box such as insulating hexagonal boron nitride (hBN), semiconducting transition metal dichalcogenides (TMDCs) and group-III monochalcogenides and metallic graphene, for fast switching semiconductor devices.

In the seminar, I will present the electronic and optoelectronic applications of graphene, transition metal dichalcogenides (MoS2, WS2) and group-III monochalcogenides (GaS, GaSe, GaTe). Infrared and ultraviolet photodetectors based on reduced graphene oxide, graphene nanoribbons and few layer molybdenum disulfide (MoS2) will be presented. I will also talk about the electronic and mechanical properties of monolayer MoS2 and WS2 grown via chemical vapor deposition (CVD). In addition to 2D TMDCs, the presentation will cover the elastic properties and breaking strengths of suspended GaS, GaSe and GaTe nanosheets measured using atomic force microscopy. The governing mechanics of crossover from plate-like regime (thick layers) to membrane- like regime (ultrathin layers) will be discussed. Electromechanical resonators based on gallium telluride and gallium sulphide operating at high frequencies (10-25 MHz) will be demonstrated. I will summarize by sharing recent results on charge transfer in 2D MoS2/GaTe and WS2/GaTe heterojunctions followed by future directions.