Temperature dependent Raman and photoluminescence of vertical WS₂/MoS₂ monolayer heterostructures

Heterostructures from two-dimensional transition-metal dichalcogenides MX₂ have emerged as a hot topic in recent years due to their various fascinating properties. Here, we investigated the temperature dependent Raman and photoluminescence (PL) spectra in vertical stacked WS₂/MoS₂ monolayer heterostructures. Our result shows that both E¹_2g and A_1g modes of WS₂ and MoS₂ vary linearly with temperature increasing from 300 to 642K. The PL measurement also reveals strong temperature dependencies of the PL intensity and peak position. The activation energy of the thermal quenching of the PL emission has been found to be equal to 69.6meV. The temperature dependence of the peak energy well follows the band-gap shrinkage of bulk semiconductor.