Physical properties of α-MnS films synthesized by hydrothermal method and photodiode applications

Abstract In this study, a heterojunction photodiode with an Au/α-MnS/p-Si/Al architecture was fabricated via the spin-coating technique. The structural and morphological analyses of the hydrothermally synthesized α-MnS thin films revealed a polycrystalline cubic rock-salt structure with a direct bandgap of 3.4 eV. The electrical and optoelectronic properties of the fabricated device were investigated using current-voltage (I-V) and transient photocurrent measurements under various illumination intensities (20–100 mW/cm²). The device exhibited distinct rectifying behavior, with the barrier height decreasing from 0.79 eV to 0.53 eV under illumination. Key performance parameters, including photosensitivity (S), photoresponsivity (R), and specific detectivity (D * ), were calculated to evaluate the device’s potential as a photodetector. The results showed a supralinear photocurrent response (m = 1.4), leading to peak performance values of S = 8.56, R = 8.73 × 10 − 5 A/W, and D * =1.53 × 10 8 Jones at 100 mW/cm². These findings demonstrate that the α-MnS/p-Si heterojunction is a functional photosensor with light-dependent switching characteristics.