Role of Monoethanolamine Concentration for Physical Properties of Cu2CoSnS4 Nanoparticles via One-Pot Hydrothermal Synthesis: Toward Low Temperature, High Performance Nanocrystalline CCTS Photodetectors by Hybrid UV-Vacuum Annealing

Abstract Herein, monoethanolamine(MEA) content effects on crystal phase, chemical composition, morphology for Cu 2 CoSnS 4 (CCTS) nanoparticles synthesized via hydrothermal process are intensively studied by using XRD, Raman, pH monitoring, and others. For two-terminal photodetectors based on CCTS nanoparticles, hybrid annealing process (i.e., vacuum annealing followed by UV irradiation) is more effective to improve electrical and photo-responsive properties, as compared with only either UV irradiation or vacuum annealing. Two-terminal CCTS photodetectors based on hybrid annealing yield the improved contact resistance (R c =6.49 ± 1.8kΩ), sheet resistance (R sh =2.19 ± 0.32kΩ/cm), photosensitivity (S ph =37%), photo responsivity (R ph= 1.60A/W), detectivity (D ph =2.62×10 10 Jones), at least better than individual annealing condition as above. More importantly, the hybrid annealing process is potentially beneficial for high performance, low temperature CCTS device implementation for envisioned flexible electronic applications.