Fluorescence Characteristics Of Single-layer WS₂ And Its Application And Research In Photonic Integrated Devices

The two-dimensional transition metal chalcogenides possess the advantages of direct band gap,strong light-substance interaction,high carrier mobility,and exciton binding energy,suited for applications in the field of optoelectronics.They also have excellent mechanical properties,and are compatible with CMOS process without considering lattice matching,attracting great research interest in the field of on-chip optical interconnects and flexible optoelectronic devices.But these characteristics are easily influenced by environment,such as substrate,doping and strain.In this paper,the fluorescence spectra of WS₂ in air and under vacuum were studied under long-term laser irradiation.It was found that the molecules in air and attached to the substrate have chemical reaction with WS₂ under the condition of laser irradiation,resulting in doping of WS₂ and the change of its spectra.In this paper,an all-optical modulator compatible with CMOS technology based on WS₂ is proposed.532 nm light is used as the pump light and 640 nm light is used as the signal light.The extinction ratio of the modulator is more than 10 dB and the overall signal gain achieved is approximately one order of magnitude.As for the fabrication of flexible optoelectronic devices,a method of transferring Si₃N₄ disks on silicon substrate to PET by exfoliation is proposed in this paper,and a flexible sample based on WS₂ is fabrication.The fluorescence spectra of the sample is measured,which lays a foundation for flexible optoelectronic devices based on two-dimensional materials in the future.