Band Gap Engineering with Ultralarge Biaxial Strains in Suspended Monolayer MoS 2

We demonstrate the continuous and reversible tuning of the optical band gap of suspended monolayer MoS2 membranes by as much as 500 meV by applying very large biaxial strains. By using chemical vapor deposition (CVD) to grow crystals that are highly impermeable to gas, we are able to apply a pressure difference across suspended membranes to induce biaxial strains. We observe the effect of strain on the energy and intensity of the peaks in the photoluminescence (PL) spectrum and find a linear tuning rate of the optical band gap of 99 meV/%. This method is then used to study the PL spectra of bilayer and trilayer devices under strain and to find the shift rates and Grüneisen parameters of two Raman modes in…

• BU
  Boston University
• DO
  Division of Materials Research

  Award: DMR-1411008
• DO
  Division of Graduate Education

  Award: DGE-1247312
• DO
  Division of Civil, Mechanical and Manufacturing Innovation

  Award: CMMI 1054406
• AF
  Air Force Office of Scientific Research