Resonant Light-Induced Heating in Hybrid Cavity-Coupled 2D Transition-Metal Dichalcogenides

Hybrid structures based on integration of two-dimensional (2D) transition-metal dichalcogenides (TMDCs) with optical resonators have recently earned significant attention. The enhanced interaction of light with 2D materials in such hybrid structures can enable devices such as efficient light-emitting diodes and lasers. However, one of the factors affecting the performance of such devices is the effect of the optically induced heat on the optoelectronic properties of the 2D materials. In this study, we systematically investigate principal roots of heat generation in hybrid cavity-coupled few atomic-layer-thick 2D TMDC films under optical pumping. The optical resonator exploited here is a Fabry-Perot (FP) resonator, which can enhance the light-MoS2 interaction by a significant factor of 60 at its resonance wavelength. We have combined an accurate theoretical modeling with experimental Raman spectroscopy to determine the roots of heat generation in MoS2 films integrated with FP resonators. Our investigations reveal that the strong modulation of light absorption in the MoS2 film, induced by excitation of an FP cavity at its resonant frequency, plays the primary role in excess heat generation in 2D materials. Furthermore, through varying the cavity length, we show that on-resonance and off-resonance excitation of the cavity results in completely different temperature profiles in the cavity-coupled MoS2 films. Also, by changing the resonance medium of the FP cavity (SiO2 and air), we take into account the role of the heat sinking effect of the substrate in heat generation in MoS2 films. In this study, the temperature-dependent red-shift of the Raman spectra is employed to monitor the local temperature of the MoS2 films. Our results show the importance of the heating effect in such hybrid structures and represent a step forward for the design of practical hybrid optical devices based on layered semiconducting 2D materials.