title: Surface effects on electronic transport of 2D chalcogenide thin films and nanostructures.
abstract: The renewed interest in two-dimensional materials, particularly transition metal dichalcogenides, has been explosive, evident in a number of review and perspective articles on the topic. Our ability to synthesize and study these 2D materials down to a single layer and to stack them to form van der Waals heterostructures opens up a wide range of possibilities from fundamental studies of nanoscale effects to future electronic and optoelectronic applications. Bottom-up and top-down synthesis and basic electronic properties of 2D chalcogenide materials have been covered in great detail elsewhere. Here, we bring attention to more subtle effects: how the environmental, surface, and crystal defects modify the electronic band structure and transport properties of 2D chalcogenide nanomaterials. Surface effects such as surface oxidation and substrate influence may dominate the overall transport properties, particularly in single layer chalcogenide devices. Thus, understanding such effects is critical for successful applications based on these materials. In this review, we discuss two classes of chalcogenides - Bi-based and Mo-based chalcogenides. The first are topological insulators with unique surface electronic properties and the second are promising for flexible optoelectronic applications as well as hydrogen evolution catalytic reactions.
authors.affiliation: Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT USA.
authors.forename: Yeonwoong
authors.initials: Y
authors.lastname: Jung
authors.affiliation: Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Shen
authors.affiliation: Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT USA ; Energy Science Institute, Yale University West Campus, West Haven, CT USA.
authors.forename: Judy J
authors.initials: JJ
authors.lastname: Cha
keywords: Bi2Se3; MoS2; Surface effects; Topological insulators; Transition metal chalcogenides; Two-dimensional materials