Giant excitation induced bandgap renormalization in TMDC monolayers

Optical absorption and gain spectra in MoS2 monolayers with thermal carrier distributions are calculated from the combined gap and Dirac-Bloch equations. It is shown that the excited carriers lead to a bandgap renormalization as large as 800 meV for a suspended monolayer MoS2. Above the critical density, optical gain is obtained over an approx. 400 meV broad spectral range above the gap. Whereas the absorption spectra in the low density regime are very sensitive to the dielectric environment, the spectra become purely intrinsic at elevated carrier densities.