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Strain-Engineered Growth of Two-Dimensional Materials

Schematic of the process through which strain is realized during the growth of 2D materials via mismatch in substrate and transition metal dichalcogenides (TDMC) thermal coefficient of expansion (TCE). Experimentally realized strains in WSe2 ranged from (a) 1% tensile strain in Silica, (b) no strain in Sapphire, to (c) 0.2% compressive strain in Strontium Titanate.

Scientific Achievement
Developed a new method to achieve built-in and tunable strain in two-dimensional materials directly via growth.

Significance and Impact
The ability to realize built-in strain for 2D materials allows for controlled modification of band structure that can lead to more efficient devices and further exploration of the underlying physics.

Research Details

  • Obtained both tensile and compressive strain engineering.
  • Achieved direct bandgap bilayer WSe2 on a rigid substrate via tensile strain.
  • Observed brightening of the dark exciton in tensile strained monolayer WSe2.

G. H. Ahn, M. Amani, H. Rasool, D.-H. Lien, J. P. Mastandrea, J. W. Ager III, M. Dubey, D. C. Chrzan, A. M. Minor, A. Javey. Strain-engineered growth of two-dimensional materials. Nature Comm. 8:608 (2017)