Control of biaxial strain in single-layer molybdenite using local thermal expansion of the substrate

Gerd Plechinger, Andres Castellanos-Gomez, Michele Buscema, Herre S.J. Van Der Zant, Gary A. Steele, Agnieszka Kuc, Thomas Heine, Christian Schüller, Tobias Korn

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Abstract

Single-layer MoS2 is a direct-gap semiconductor whose electronic band structure strongly depends on the strain applied to its crystal lattice. While uniaxial strain can be easily applied in a controlled way, e.g., by bending of a flexible substrate with the atomically thin MoS2 layer on top, experimental realization of biaxial strain is more challenging. Here, we exploit the large mismatch between the thermal expansion coefficients of MoS2 and a silicone-based substrate to apply a controllable biaxial tensile strain by heating the substrate with a focused laser. The effect of this biaxial strain is directly observable in optical spectroscopy as a redshift of the MoS2 photoluminescence.Wealso demonstrate the potential of this method to engineer more complex strain patterns by employing highly absorptive features on the substrate to achieve non-uniform heat profiles. By comparison of the observed redshift to strain-dependent band structure calculations, we estimate the biaxial strain applied by the siliconebased substrate to be up to 0.2%, corresponding to a band gap modulation of 105 meV per percentage of biaxial tensile strain.

Original languageEnglish
Article numberA20
Journal2D Materials
Volume2
Issue number1
DOIs
Publication statusPublished - 2015 Mar 16

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All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Plechinger, G., Castellanos-Gomez, A., Buscema, M., Van Der Zant, H. S. J., Steele, G. A., Kuc, A., Heine, T., Schüller, C., & Korn, T. (2015). Control of biaxial strain in single-layer molybdenite using local thermal expansion of the substrate. 2D Materials, 2(1), [A20]. https://doi.org/10.1088/2053-1583/2/1/015006