Characterization of Transferred Graphene Based Solar Cell

Graphene is a two-dimensional material which is flexible and has a high conductivity. We grow a single layer graphene through chemical vapor deposition (CVD). Graphene which is grown by CVD has single layer and large specific surface area about 2620 m 2 /g, theoretically. Among the properties of graphene, high electrical conductivity and transparency are important advantages as an emerging material of solar cell. Using Schottky barrier at the interface between graphene and Si, solar cells have been developed. In order to enhance the solar cell efficiency, IV characteristics of the Schottky junction have been studied. We use CVD graphene grown on copper foil and silicon wafer (n-doped , 1-10 Ohm·cm, 300 nm oxide, LG Siltron). First, (5x5 mm 2 ) window pattern is exposed on silicon through photolithography. The oxygen layer of the patterned area is removed using BOE (7:1 water:HF) for 4 minutes. The photoresist is removed in acetone at least 10h. A square shape electrode with Ti (10 nm)/Au (90 nm) is deposited on silicon oxide. Ag (300 nm) is deposited on backside of silicon and annealed to have an Ohmic contact. After all these processes are finished, graphene was transferred. Doping on graphene is one way to increase the efficiency of Schottky junction solar cell. We compare none-doped graphene with chemically doped graphene by HNO 3 and bis (trifluoromethanesulfonyl) amide. This could be an alternative for the cheap and environmentally friendly solar cell in the future.