Optical transitions and selection rules in 2D semiconductors. (New)

Inspired by the unusual properties of graphene, the search for other 2D materials has unveiled that MoS2 monolayers also offer unusual and spectacular characteristics. In contrast to gapless graphene, MoS2 is perfectly adapted for logic electronics and optoelectronics with a gap of 1.8 eV. In addition, excellent transistor performance, long device lifetime, and high mechanical strengthmake MoS2 an ideal material for the development of transparent displays and other flexible electronic applications. However, the properties of this promising 2D material remains to be unveiled, as little is known on its electrical, optical and mechanical properties. One of the most fundamentally characteristic of a material is its band structure close to the Fermi level: it determines most of the optical and electronic properties.

This project consist in providing the experimental values for reconstructing the band structure. Using electroreflectance spectroscopy in a wide spectral range, the student will determine all optically allowed optical transitions, along with their polarization selection rules. Using this information, the student will unveil the evolution of main critical points as a function of the number of monolayers and as a function of perturbations like temperature, strain and magnetic field.

Faculty Supervisor:

Sebastien Francoeur

Student:

Ganesh Omar

Partner:

Discipline:

Physics / Astronomy

Sector:

University:

Program:

Globalink