title: Optoelectronic crystal of artificial atoms in strain-textured molybdenum disulphide.
abstract: The isolation of the two-dimensional semiconductor molybdenum disulphide introduced a new optically active material possessing a band gap that can be facilely tuned via elastic strain. As an atomically thin membrane with exceptional strength, monolayer molybdenum disulphide subjected to biaxial strain can embed wide band gap variations overlapping the visible light spectrum, with calculations showing the modified electronic potential emanating from point-induced tensile strain perturbations mimics the Coulomb potential in a mesoscopic atom. Here we realize and confirm this 'artificial atom' concept via capillary-pressure-induced nanoindentation of monolayer molybdenum disulphide from a tailored nanopattern, and demonstrate that a synthetic superlattice of these building blocks forms an optoelectronic crystal capable of broadband light absorption and efficient funnelling of photogenerated excitons to points of maximum strain at the artificial-atom nuclei. Such two-dimensional semiconductors with spatially textured band gaps represent a new class of materials, which may find applications in next-generation optoelectronics or photovoltaics.
authors.affiliation: Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Alex W
authors.initials: AW
authors.lastname: Contryman
authors.affiliation: Department of Materials Science and Engineering, Dwight Look College of Engineering, Texas A&M University, College Station, Texas 77843, USA.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Qian
authors.affiliation: Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Sina Moeini
authors.initials: SM
authors.lastname: Ardakani
authors.affiliation: Department of Materials Science &NanoEngineering, Rice University, Houston, Texas 77251, USA.
authors.forename: Yongji
authors.initials: Y
authors.lastname: Gong
authors.affiliation: Department of Materials Science &NanoEngineering, Rice University, Houston, Texas 77251, USA.
authors.forename: Xingli
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Jeffery M
authors.initials: JM
authors.lastname: Weisse
authors.affiliation: Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Chi Hwan
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Jiheng
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Materials Science &NanoEngineering, Rice University, Houston, Texas 77251, USA.
authors.forename: Pulickel M
authors.initials: PM
authors.lastname: Ajayan
authors.affiliation: Department of Nuclear Science and Engineering and Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Ju
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Hari C
authors.initials: HC
authors.lastname: Manoharan
authors.affiliation: Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zheng