© 2020, Springer Science+Business Media, LLC, part of Springer Nature.The cobalt sulfate-polyvinylpyrrolidone (CoSO4-PVP) solution was deposited on n-Si crystal by using spin-coated method. The electrical and photoresponse properties of Au/(CoSO4-PVP)/n-Si MPS diode were investigated both in the dark and under illumination (100 mW/cm2) level. MPS-type diode exhibits good rectifying behavior in dark condition. The measured reverse current under illumination was found to be higher than dark condition. The MPS diode has also a good response to the illumination and photosensitivity value was found as 5.25 × 103 for 100 mW/cm2. The diode parameters such as n, Φb0 and Rs were extracted based on both the thermionic-emission (TE) and Norde method. The current conduction mechanisms of the MPS diode were also analyzed by forward ln(IF)-ln(VF) and reverse ln(IR)-VR1/2 plots. Moreover, both the voltage dependence of C and G characteristics were investigated under 1 MHz. The other electrical parameters such as V0, VD, ND, EF, WD and ΦB were extracted from the C−2–V characteristics. Besides, the voltage dependence profile of the Nss was extracted by using dark-illumination capacitance (Cdark-Cill) measurements at a frequency of 1 MHz. The results suggest that the prepared Au/(CoSO4-PVP)/n-Si MPS diode can be used in optoelectronic device applications.