Few-layer PdSe2 -based field-effect transistor for photodetector applications

We demonstrate a multilayer palladium diselenide (PdSe2) high-performance photodetector. The photodetector exhibits the photodetectivity of 0.15 x 10(10) Jones under laser illumination (lambda = 655 nm and power of 0.057 mWmm(-2)). The negative threshold voltage shift in transfer characteristics upon laser illumination is mainly attributed to the photogating effect. Systematic analysis of experimental data indicates that the photogating effect and space charge limited conduction are simultaneously involved in the conduction mechanism. We observe that the photogenerated current increases logarithmically as the light intensity increases, and it persists (similar to 200 s) even after stopping the illumination. The slow decrease in current was attributed to the trapping of photogenerated charge carriers at the PdSe2/SiO2 interface and the defects in the structure of PdSe2. We also observe a reproducible and stable time-resolved photoresponse with respect to the incident laser power. We believe that this study can be an important source of information and can help researchers to continue to investigate methods that would allow them to maximise the potential of PdSe2 for photodetector applications.