Physical and electrical characterization of junction between single-layer graphene (SLG) and Ti prepared by various processes

The junction contact characteristics between single layer graphene (SLG) and Ti, where Ti is prepared by various deposition processes, are investigated physically (via Raman) and electrically (via 2-point or 4-point probe measurement and residual resistance methods). For Ti deposited by electron beam evaporation (EBM) process, there are no noticeable Raman shift and weak D band in Ti junction with SLG. On the other hand, D band and Raman shift becomes visible when Ti is prepared using sputter process, indicating the disorder related defects and the change of lattice constant in graphene. On the electrical property, it is observed that the contact resistance of Ti/graphene prepared by sputter process is larger than that by EBM process, which can be attributed to process induced defect in graphene.