Strain engineering effects on the optical properties of bilayer MoS₂

Two-dimensional (2D) materials like transitional metal dichalcogenides (TMDs) exhibit interesting optical, mechanical, and electronic properties. These properties can be manipulated in several ways, one of them being strain engineering. By applying strain to very thin layers of TMDs, we can change properties like photoluminescence and absorption for these materials by causing their bandgap to change under strain. In our experiment, we prepared Al₂O₃ pillars on a silicon substrate. Then a MoS₂ bilayer, encapsulated in hBN, was transferred on the pillars via dry transfer technique. Photoluminescence and white light absorption measurements were carried out at low temperature (5K) to understand the effect of strain on the excitonic properties.