Low-temperature photoluminescence emission of monolayer MoS2 on diverse substrates grown by CVD

Abstract

Monolayer MoS2 films on three different substrates, SiO2/Si, quartz and sapphire are synthesized by the method of chemical vapor deposition (CVD). Through a series of the optical characterization methods, the films are confirmed to be uniform and continuous on micrometer scale with a reliable quality. Low-temperature photoluminescence (PL) properties of monolayer MoS2 on diverse substrates are primarily studied. As the temperature increases, a decrease in PL intensity and a red shift in PL wavelength are observed. This is because the thermal motion of the phonons becomes stronger, which means that the nonradiative recombination increases and the PL intensity decreases. And the reduction of semiconductor band gap contributes to the redshift of PL. Furthermore, the influence of the lattice structure and thermal conductivity of the substrate on the low-temperature PL of monolayer MoS2 is also discussed.