Capacitance-Voltage Investigation of Encapsulated Graphene/Silicon Solar Cells

In this article, the effect of graphene/silicon Schottky junction solar cells (G/Si SJSCs) encapsulation is investigated in terms of capacitance-voltage (C-V) curves in the forward bias region. Capacitance behavior can give accurate information on interface properties, especially when it is considered at positive voltage. The detection of a double peak on such curve is related to nonuniform interface properties at the graphene/silicon interface. To passivate the interface, G/Si SJSCs have been exposed to HNO $_{\text{3}}$ vapors and the effectiveness of HNO $_{\text{3}}$ doping has been exploited as well as its volatility, assessing the need for encapsulation. C-V curves collected over time from doped unencapsulated G/Si SJSCs clearly exhibited a modification of capacitance behavior, revealing a fading of doping beneficial effects over a week. On the contrary, C-V curves acquired from encapsulated samples evidence that capacitance behavior did not modify over time.