Study on the properties of MoS2 thin films and devices prepared under different annealing pressures

MoS2, characterized by its tunable bandgap, high optical absorption coefficient, and excellent carrier mobility, demonstrates outstanding performance in photoelectric and semiconductor devices. This study addresses the high-density defect distribution typically found in MoS2 thin films prepared by employing a gate-assisted magnetron sputtering method combined with postannealing. The effects of various annealing pressures on the microstructure and electrical properties of the MoS2 thin films were systematically investigated. It was observed that an appropriate increase in the annealing pressure enhances the crystallinity of the MoS2 thin films while reducing the interface recombination in devices. At an annealing pressure of 150 Pa, high-quality, compositionally pure MoS2 thin films with optimal electrical properties were obtained, exhibiting a resistivity of 16.1 Ω cm and a Hall mobility of 682.5 cm2/(V s). Furthermore, the modulation of annealing pressure was found to significantly improve the performance of MoS2/SnO2/p-Si heterojunction solar cells. Under an annealing pressure of 150 Pa, the device achieved a notable enhancement in performance metrics, including an open-circuit voltage (Voc) of 344 mV, a short-circuit current density (Jsc) of 33 mA/cm2, a fill factor of 57%, and a power conversion efficiency of 6.02%. The external quantum efficiency reached 90.7%. The devices also exhibited excellent rectification behavior, with a rectification ratio of 7.58 × 103 and an ideality factor (n) of 1.062.