4 research outputs found
Optoelectronic crystal of artificial atoms in strain-textured molybdenum disulphide
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
Erratum: Corrigendum: Activating and optimizing MoS2 basal planes for hydrogen evolution through the formation of strained sulphur vacancies
ARTICLE Optoelectronic crystal of artificial atoms in strain-textured molybdenum disulphide
Phase Separation of Dirac Electrons in Topological Insulators at the Spatial Limit
In
this work we present unique signatures manifested by the local electronic
properties of the topological surface state in Bi<sub>2</sub>Te<sub>3</sub> nanostructures as the spatial limit is approached. We concentrate
on the pure nanoscale limit (nanoplatelets) with spatial electronic
resolution down to 1 nm. The highlights include strong dependencies
on nanoplatelet size: (1) observation of a phase separation of Dirac
electrons whose length scale decreases as the spatial limit is approached,
and (2) the evolution from heavily n-type to lightly n-type surface
doping as nanoplatelet thickness increases. Our results show a new
approach to tune the Dirac point together with reduction of electronic
disorder in topological insulator (TI) nanostructured systems. We
expect our work will provide a new route for application of these
nanostructured Dirac systems in electronic devices