衬底温度对V2O5修饰n-Ge异质结电学和光伏特性的影响

Abstract Electrical and photovoltaic properties of V 2 O 5 /n-Ge heterojunction were realized by the deposition of V 2 O 5 thin films at different substrate temperatures (room temperature (RT), T S = 150 °C and 250 °C). Optical properties of V 2 O 5 thin films were analysed and direct allowed transitions are found most probable. Infrared measurements of V 2 O 5 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 V 2 O 5 thin films. X-ray diffraction studies were also performed for V 2 O 5 /n-Ge heterojunctions which indicates the amorphous nature of V 2 O 5 thin films for V 2 O 5 (RT)/n-Ge heterojunction and crystallinity of the films found to be increased by increasing the substrate temperature. Current-voltage properties of V 2 O 5 /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 V 2 O 5 (T S = 150 °C and 250 °C)/n-Ge heterojunctions. Photovoltaic properties of V 2 O 5 /n-Ge heterojunctions indicate notable responsivity of V 2 O 5 thin films under illumination (100 mW/cm 2 ) at increased substrate temperature. The sensitivity of the V 2 O 5 (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 V 2 O 5 thin films on n-Ge substrate altered effectively by substrate temperature of V 2 O 5 thin films. This triggers the variation of these properties by changing the conductivity of thin films with doping or post annealing conditions.