Templated synthesis of low dimensional films and heterostructures on freestanding graphene membranes*

Low dimensional films and layered heterostructures, including topological materials and transition metal dichalcogenides, have incredible potential for a wide array of applications due to the flexibility and tunability of their unique properties.   Key challenges for realizing such potential include understanding how interfacial structure and defects affect desired properties and their incompatibility with existing nanofabrication techniques.  Here we present a “templated synthesis” approach where freestanding monolayer graphene extended over arbitrary surfaces and patterned structures is used as a substrate for the synthesis of high-quality films of topological materials and hybrid interfaces between different materials.  This approach has enabled the synthesis and direct characterization of the atomic and interfacial structure of as-grown low dimensional films and heterostructures using scanning transmission electron microscopy (STEM) for comparison to the electronic structure revealed by scanning tunneling spectroscopy (STS) and angle resolved photoemission spectroscopy (ARPES).  The templated synthesis approach also helps bridge the gap between low dimensional materials and traditional semiconductor nanofabrication techniques, opening a route towards development of device structures with novel functionality.