Abstract
Photoluminescence measurements in mono- and bilayer-MoS(2) on SiO(2) were undertaken to determine the thermal effect of the MoS(2)/SiO(2) interface on the optical bandgap. The energy and intensity of the photoluminescence from monolayer MoS(2) were lower and weaker than those from bilayer MoS(2) at low temperatures, whilst the opposite was true at high temperatures above 200 K. Density functional theory calculations suggest that the observed optical bandgap crossover is caused by a weaker substrate coupling to the bilayer than to the monolayer.