Probing the Optical Properties of MoS₂ on SiO₂/Si and Sapphire Substrates

As an important supplementary material to graphene in the optoelectronics field, molybdenum disulfide (MoS₂) has attracted attention from researchers due to its good light absorption capacity and adjustable bandgap. In this paper, MoS₂ layers are respectively grown on SiO₂/Si and sapphire substrates by atmospheric pressure chemical vapor deposition (APCVD). Atomic force microscopy, optical microscopy, and Raman and photoluminescence spectroscopy are used to probe the optical properties of MoS₂ on SiO₂/Si and sapphire substrates systematically. The peak shift between the characteristic A_1g and E¹_2g peaks increases, and the I peak of the PL spectrum on the SiO₂/Si substrate redshifts slightly when the layer numbers were increased, which can help in obtaining the layer number and peak position of MoS₂. Moreover, the difference from monolayer MoS₂ on the SiO₂/Si substrate is that the B peak of the PL spectrum has a blueshift of 56 meV and the characteristic E¹_2g peak of the Raman spectrum has no blueshift. The 1- and 2-layer MoS₂ on a sapphire substrate had a higher PL peak intensity than that of the SiO₂/Si substrate. When the laser wavelength is transformed from 532 to 633 nm, the position of I exciton peak has a blueshift of 16 meV, and the PL intensity of monolayer MoS₂ on the SiO₂/Si substrate increases. The optical properties of MoS₂ can be obtained, which is helpful for the fabrication of optoelectronic devices.