Promoting the optoelectronic and ferromagnetic properties of Cr2S3 nanosheets via Se doping

Doping can change the band structure of semiconductors, thereby affecting their electrical, optical, and magnetic properties. In this study, we describe the synthesis of two-dimensional (2D) Se-doped Cr2S3 (Se-Cr2S3) nanosheets using the chemical vapor deposition method. In these semiconductor nanosheets, the Se doping concentration can be controlled by tuning the Se/S mass ratio in the precursor. At the doping concentrations of 10.05% and 2.05%, the room temperature conductivity and mobility were increased by nearly 4 and 2 orders of magnitude, respectively. In addition, the response time of an ultrathin Se-Cr2S3 photo-detector was 200 times shorter than that of an undoped Cr2S3 nanosheet photodetector. 4.07%-Se-Cr2S3 nanosheets show ferrimagnetic behavior with a Curie temperature of ∼200 K, which is 80 K higher than that of undoped Cr2S3 nanosheets. A density functional theory calculation indicated that the Se doping can induce the formation of intercalated Cr vacancies in Se-Cr2S3 and enhance its metallic characteristics. Our results demonstrated that Se-Cr2S3 has significant potential in future electronic, optoelectronic, and spintronic devices.