Frontiers of Materials Award Symposium: Low-Dimensional Materials and Interfaces for Next Generation Computing: Session II
Program Organizers: Deep Jariwala, University of Pennsylvania
Wednesday 8:30 AM
March 17, 2021
Room: RM 6
Location: TMS2021 Virtual
8:30 AM Invited
Designing Solid-state Materials from Quantum Dots for Next-generation Electronic Devices: Cherie Kagan1; 1University of Pennsylvania
Colloidal quantum dots (QDs) are typically 2-20 nm diameter fragments of bulk semiconductors. They are known as “artificial atoms” since electrons, holes, and excitons are quantum-mechanically confined and occupy discrete electronic states. Advances in wet-chemical synthetic methods enable the preparation of QDs tailorable in size, shape, and composition. These QDs are typically capped by organic ligands and are readily dispersed in solvents. They may be assembled from dispersions to form glassy or crystalline solids. I will focus on routes to design solid-state QD materials by manipulating the QD composition, using post-assembly cation-exchange processes; the QD surface chemistry to strengthen electronic coupling, by exchanging the ligands used in synthesis for more compact chemistries; and the doping of QD solids, by introducing atoms and ions that serve as impurities or modify stoichiometry. Ultimately, I will connect QD material design to their physical properties and their application in next-generation electronic and optoelectronic devices.
9:10 AM Invited
vdW Contacts on 2D Semiconductors: Manish Chhowalla1; 1Cambridge University
Ultra-clean van der Waals interfaces can be achieved between soft indium metal and monolayer 2D transition metal dichalcogenide semiconductors. Such interfaces lead to low contact resistance and n-type field effect transistors with high mobilities – in excess of 100 cm2-V-1-s-1. It has been, however, challenging to make similarly clean interfaces between refractory metals with high work functions to achieve efficient hole injection. Here, I will present our efforts on realizing p-type contacts using high work function metals and alloys. We show that it is possible to deposit a thin layer of indium and then a high work function metal on top of it to form an alloy by annealing at 200oC. This method preserves the ultra-clean interface between the monolayer semiconductor and alloy while increasing the work function so that p-type devices can be realized. These interfaces reveal low contact resistance and also high mobility p-type devices.
9:50 AM Panel Discussion Moderator: Deep Jariwala; Panelists: Mark C. Hersam,Suman Datta,Cherie Kagan, and Manish Chhowalla