Broadband tunable resonance modes from multi-composition monolayer MoS2(1−x)Se2x with SiO2 microsphere cavity

Two-dimensional (2D) monolayer transition metal dichalcogenides (TMDCs) that are compatible with Si-based substrates have already exhibited huge application potential in optoelectronics and photonics. The MoS2(1−x)Se2x ternary alloy consisting of two different chalcogens, as a class of lasing gain medium, enriches the family of 2D TMDC materials. Here, monolayer MoS2(1−x)Se2x ternary alloys with tunable composition have been synthesized via single-step chemical vapor deposition method. Raman and photoluminescence studies demonstrate that the bandgap of grown monolayer MoS2(1−x)Se2x alloys can be gradually tuned from 1.59 to 1.82 eV, indicating the continuous changes of the chemical composition x from 0.82 to 0. The oscillation characteristic is further investigated, where the MoS2(1−x)Se2x alloy provides optical gain for the SiO2 microsphere resonant cavity. The achieved resonance modes in a broadband range from 610 to 810 nm not only extend the range of potential TMDC-based lasers, but also drive the applications of alloy materials in various optoelectronics devices.