Discovery of Burstein-Moss shift in Re-doped MoS$_2$ nanoparticles*

We investigated the optical properties of Re-doped MoS$_2$ nanoparticles and compared our findings with the pristine and bulk analogs. Our measurements reveal that confinement softens the exciton positions and reduces spin-orbit coupling whereas doping has the opposite effect. We model the doping-induced exciton blue shift in terms of the Burstein-Moss effect. These findings are important for understanding doping and finite length scale effects in model nanoscale materials.