Graphene oxide - a surprisingly good nucleation seed and adhesion promotion agent for one-step ZnO lithography and optoelectronic applications

Graphene oxide (GO), with its oxygen-containing functional groups (OFGs) attached to its surface and edges, has opened means for graphene to be used in more intriguing applications. We discovered that: ① OFGs on one side of the GO sheet provide excellent nucleation sites to grow a layer of solid ZnO film onto it; ② OFGs on the other side of the GO sheet form chemical bonds with the underlying solid substrate to provide adequate adhesion between the film and the substrate; ③ the combination of these two properties makes it feasible to perform one-step ZnO lithography for microelectronics applications; and ④ it has also made it possible for us to fabricate Ag NP doped ZnO–graphene composite thin films for surface plasmon generation, light trapping and improved solar cell efficiency. XPS analysis confirms that C–O–Si type chemical bonds form when GO was introduced onto the Si wafer surface. As it is expected that GO can also be used to nucleate other metal oxide films on different substrates, it may open a broad arena for new applications.