Electrical and photovoltaic properties of V2O5/n-Ge heterojunction were realized by the deposition of V2O5 thin films at different substrate temperatures (room temperature (RT), TS = 150 °C and 250 °C). Optical properties of V2O5 thin films were analysed and direct allowed transitions are found most probable. Infrared measurements of V2O5 thin films reveal vibrational bands which confirms the V=O and V–O–V bonds. The shift of these bands with increasing substrate temperature suggests variation in bond lengths which might be due to strain effects in V2O5 thin films. X-ray diffraction studies were also performed for V2O5/n-Ge heterojunctions which indicates the amorphous nature of V2O5 thin films for V2O5(RT)/n-Ge heterojunction and crystallinity of the films found to be increased by increasing the substrate temperature. Current-voltage properties of V2O5/n-Ge heterojunctions at different substrate temperatures were studied and found variations in barrier properties of the devices with an increase in substrate temperature. Explored forward bias current conduction mechanisms of heterojunctions reveal trap charge limited current conduction is the dominant conduction at moderately high bias potential particularly for V2O5(TS = 150 °C and 250 °C)/n-Ge heterojunctions. Photovoltaic properties of V2O5/n-Ge heterojunctions indicate notable responsivity of V2O5 thin films under illumination (100 mW/cm2) at increased substrate temperature. The sensitivity of the V2O5(150 °C)/n-Ge heterojunction was found to be maximum than other heterojunctions whereas the photoresponsivity and specific detectivity of the heterojunction shows significant variation with bias and substrate temperature. The electrical and photoresponsive properties of V2O5 thin films on n-Ge substrate altered effectively by substrate temperature of V2O5 thin films. This triggers the variation of these properties by changing the conductivity of thin films with doping or post annealing conditions.