Title：Possible Routes towards Challenges in 2D Semiconductors from First-Principles: Chemical Doping and Carrier Mobility

Speaker：Yang Jihui  Fudan University

Time：Nov. 26,2022 14:00pm

Online report（Tencent ID: 819-259-810 Password:2022）

Abstract：Ever since the discovery of graphene, two-dimensional (2D) semiconductors have attracted intensive research interests due to their novel physics and potential applications. So far, there are more than one thousand of 2D materials that have been discovered either theoretically or experimentally and some of them have been made into 2D devices such as FETs and p-n junctions, which are expected to complement traditional 3D devices with the Moore's law approaching physical limit. However, from conceptual to practical 2D semiconductor devices, many challenges need to be overcome. Here in this talk, I will present our first-principles works aiming to offer possible routes towards the two challenges in 2D semiconductors, which are the chemical doping difficulty and low carrier mobility problem. For the first challenge, the physical mechanisms behind chemical doping difficulty in 2D are revealed and demonstrated by first-principles calculations, based on which strategies are proposed to improve doping efficiencies. For the second challenge, the carrier scattering mechanisms in 2D are understood using our proposed phonon-energy-resolved properties. The general rules based on easily-calculated fundamental electronic and phonon properties for screening possible high-mobility 2D semiconductors are established, guided by which we have found several high-mobility systems and confirm their mobility properties using first-principles calculations and considering all electron-phonon couplings. These works will be helpful for the further development of 2D devices.