(Invited) Growth of Van Der Waals Materials: New Insights from Real-Time Studies

Abstract

The existence of thousands of new 2D materials has been predicted and several of them have been fabricated, mostly by exfoliation from bulk crystals. In addition to their attractive properties, the availability of these 2D materials also creates a wealth of opportunity to engineer complex van der Waals (vdW) heterostructures, thus laying the groundwork to tailor manipulate the basic properties and device performances. However, despite its numerous advantages, this class of materials is yet to be integrated in real technological applications due to several challenges such as the lack of scalable fabrication processes. With this perspective, quasi-epitaxial growth methods have recently been explored to synthesize 2D materials and vdW heterostructures. Herein, by using group V 2D materials as a model system, this presentation will address the current understanding of vdW growth and the key mechanisms governing the nucleation, growth and stability on weakly interacting surfaces. New insights on the interplay between kinetics and thermodynamic driving forces will be described and discussed based on in situ low-energy electron microscopy and diffraction (LEEM/LEED) studies. The combination of LEEM and LEED with ex situ characterization methods allowed us to elucidate the growth mechanisms of stable and metastable 2D-Sb allotropes and 2D-AsSb alloys on conventional semiconductor substrates and graphene. These results lay the groundwork for the development of scalable vdW epitaxial growth methods for emerging 2D materials and vdW heterostructures.Acknowledgment:The authors acknowledge contributions from Robert Jacobberge, Hannes Zschiesche, Andrea Locatelli, Tevfik O. Menteş, Olga Waller, Charles-Antoine Deslauriers, Francesca Genuzio, Gianluigi Botton, Michael S. Arnold.