The research areas of beyond graphene 2D and layered materials remain highly active and are continuously expanding. This is particularly true with many growth techniques emerging as promising methods for controlled large-scale synthesis of single monolayers and heterostructures. This tutorial will showcase the current status and future directions in the area of large-scale synthesis, doping and alloying of 2D materials and van der Waals heterostructures. Specifically, this tutorial will cover the science and practice of molecular beam epitaxy (MBE), metal–organic chemical vapor deposition (MOCVD) and solution-phase processing approaches that will ultimately enable the practical development of wafer scale electronics from beyond graphene 2D and layered materials.
Molecular Beam Epitaxy of 2D Layered Materials
Christopher Hinkle, University of Notre Dame
Molecular beam epitaxy (MBE) can enable high-quality 2D layered chalcogenides through the combination of high purity elemental sources and an ultra-high vacuum growth environment. This tutorial will cover the science and practice of MBE as it pertains to the growth of van der Waals bonded chalcogenide films and their heterostructures. Fundamental nucleation and growth behavior of transition-metal dichalcogenides by MBE will be discussed, focusing on important parameters to control domain orientation and grain size in MBE to achieve wafer-scale grown films. This tutorial will also feature novel advances in MBE system designs and highly developed in situ materials characterization techniques to enable the fundamental understanding of the growth thermodynamics and kinetics, the structure of these van der Waal monolayers and abruptness of heterostructures.
2:30 pm BREAK
Metal–Organic Chemical Vapor Deposition of 2D Layered Materials
Joan M. Redwing, The Pennsylvania State University
Metal–organic chemical vapor deposition (MOCVD) has emerged as a promising method for the synthesis of wafer-scale epitaxial films of monolayer transition-metal dichalcogenides (TMDs) and related 2D materials. This tutorial will cover the science and practice of MOCVD as it pertains to the growth of van der Waals bonded chalcogenide films. Practical considerations including reactor design, precursor selection, growth conditions and substrates will be reviewed. The role of kinetics and thermodynamics in the nucleation, domain shape and lateral versus vertical growth will be discussed. Characterization techniques for wafer-scale monolayer films as well as prospects for future advances, including in situ characterization and layer-by-layer growth of heterostructures, will be detailed.
Liquid Phase Exfoliation of 2D Layered Materials and Applications
Mark C. Hersam, Northwestern University
Beyond conventional crystal growth techniques, liquid phase exfoliation of 2D sheets from layered bulk crystals represents a viable solution for producing monolayer films on a wafer scale through standard processing technologies such as spin coating and roll-to-roll manufacturing. Here, we review different strategies for exfoliation of 2D and layered materials in the liquid phase and discuss important parameters that govern the thickness and lateral size of the exfoliated sheets. Practical considerations on the role of surfactants and dispersing solvent medium as well as control of concentration and viscosity of dispersed exfoliated 2D sheets will also be highlighted. This tutorial will provide practical guidelines for the process of liquid phase exfoliation that may be generalized to different types of layered materials, with a short discussion on the impact of this process on device applications.