Nonblinking, intense two-dimensional light emitter: monolayer WS2 triangles

ACS Nano. 2013 Dec 23;7(12):10985-94. doi: 10.1021/nn4046002. Epub 2013 Nov 27.


Monolayer WS2 (1L-WS2), with a direct band gap, provides an ideal platform to investigate unique properties of two-dimensional semiconductors. In this work, light emission of a 1L-WS2 triangle has been studied by using steady-state, time-resolved, and temperature-dependent photoluminescence (PL) spectroscopy. Two groups of 1L-WS2 triangles have been grown by chemical vapor deposition, which exhibit nonuniform and uniform PL, respectively. Observed nonuniform PL features, i.e., quenching and blue-shift in certain areas, are caused by structural imperfection and n-doping induced by charged defects. Uniform PL is found to be intrinsic, intense, and nonblinking, which are attributed to high crystalline quality. The binding energy of the A-exciton is extracted experimentally, which gives direct evidence for the large excitonic effect in 1L-WS2. These superior photon emission features make 1L-WS2 an appealing material for optoelectronic applications such as novel light-emitting and biosensing devices.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biosensing Techniques / methods*
  • Crystallization
  • Kinetics
  • Lasers
  • Light
  • Luminescence
  • Materials Testing
  • Microscopy, Atomic Force
  • Nanotechnology
  • Optics and Photonics
  • Photochemistry
  • Semiconductors
  • Spectrophotometry
  • Spectrum Analysis, Raman / methods*
  • Temperature