Diffusion-assisted metallic invasion into graphene oxide layer in metal/graphene oxide/metal structures

Diffusion of metallic content into graphene oxide (GO) thin film layers prepared over metallic surfaces is demonstrated in GO/metal ( M 1 = ITO, Al, Au) and metal ( M 2 = Al, Au)/GO/ M 1 = ITO, Al, Au) device structures. Depth profile XPS provides the presence of metallic content identical to the metal contact inside the GO films. The metallic content in GO films is attributed to the diffusion of metal atoms through the defect sites of GO sheets in the M 2 /GO/M 1 structures and dominates the electronic conduction. The temperature-dependent current–voltage ( I – V ) characteristics provide temperature coefficient of resistance ( α ) equivalent to the metallic contact, suggesting the diffusion of metallic contents into the GO films and connecting both electrodes. The I – V measurements in combination with XPS measurements suggest migration of Al or Au atoms from the electrodes through the defect sites of GO to the other electrode and that dominates electrical conduction. Graphical abstract