(287a) Invited: Chemical, Interfacial, and Opto/Electronic Properties of CVD Grown Graphene, hBN, MoS2, WS2 and Their Heterostructures  

This presentation will discuss the bond-hybridization, interfacial interactions and chemical manipulations of 2D nanomaterials to achieve 2D heterostructures and a control on their functionalities. The talk will include three topics: (a) ring-centered functionalization of graphene, (b) hBN growth for heterostructures, and (c) MoS₂ and WS₂ hetero-photovoltaics. (A) A large-area, vapor-phase, ‘ring-centered’ hexahapto (h⁶) functionalization of graphene will be shown. The chemical structure produced is applied to create nucleation-sites for the growth of nanoparticles (AgNPs) without disrupting its sp² character. This non-destructive functionalization preserves the lattice continuum with a retention in charge carrier mobility. Further, with AgNPs attached on graphene/n-Si solar cells, an 11-fold plasmonic-enhancement in the power conversion efficiency (1.24%) is achieved. (B) A novel mechanism of direct growth of large-scale h-BN on silicon based substrates via chemical vapor deposition (CVD) will be shown. This process is leveraged to achieve hBN heterostructures with graphene, MoS₂ and WS₂. The enhanced electrical and optoelectronic properties of these heterostructures will be discussed. (C) MoS₂ and WS₂ are attractive 2D nanomaterials for their inimitable electronic band structures with indirect-to-direct bandgap transition, semiconductor-to-metal lattice-phases, and the large excitonic effect. Here, we show the photovoltaic response of WS₂/Si and MoS₂/Si heterojunction solar cells fabricated via CVD. The photo-response and quantum efficiency of these devices will also be shown. The combined work presented here will provide a chemical tool-kit to manipulate the structural and interfacial properties of 2D nanomaterials and their heterostructures for enhanced device architectures and functionalities.