(Invited) Electronics Based on Monolayers

Transition metal dichalcogenides (TMDs) are attractive for energy and electronic applications. Our recent success in vapor phase growth of TMD monolayer [1] has stimulated the research in growth and applications [2].  In this presentation,  I would discuss the synthesis and characterizations of crystalline MoS₂ and WSe₂ monolayers. These layer materials can be transferred to desired substrates, making them suitable building blocks for constructing multilayer stacks for various applications [3].

Heterostructures of 2d materials formed by vertical stacking have been realized recently via transfer of their exfoliated flakes, where their properties are dominated by the stacking orientation and strength of interlayer coupling. The method to determine valence band and conduction band alignment for various TMD materials is proposed [4].

Another very attractive structure is lateral heterostructure in which the junction is atomically sharp and the active region can be as narrow as few strings of atoms at the junction areas. This structure offers much easier band offset tuning since materials are spatially separated. The direct growth of such lateral heterostructures will be presented. Preliminary results and perspectives on monolayer electronics shall be discussed.

[1] Adv. Mater. 24, 2320 (2012); ACS Nano 8, 923 (2014).   [2] Nat. Chem. 5, 263-275 (2013); Chem. Soc. Rev. (2015) DOI: 10.1039/C4CS00256C.    [3] ACS Nano 8, 2951 (2014); ACS Nano 8, 8317 (2014). [4] arXiv:1406.5137 (2015)