Fabrication of planar junctions in Graphene sheets using Focused Ion Beam

In this paper we present about fabrication of planar-type structures in thinner graphite sheets (thickness ~ 300 ㎚) using focused ion beam (FIB). We have studied temperature dependent transport characterization for these planar-type structures. Highly oriented pyrolytic graphite (HOPG) is a periodical stack of two dimensional (2-D) graphite sheets along the c-axis. The interlayers of graphite are loosely bonded each other with weak Van der waals forces. We describe a technique for preparing micronscale graphite sheets out of bulk graphite, method of electrical ohmic contacts and fabrication of planar-type structures in graphite sheet using focused ion beam (FIB). We also report the temperature dependence transport characteristics for several sizes of planar-type structures patterned in graphite flakes. We have observed semiconducting behavior and a small drop in resistance during the temperature down to 30 K. This paper will further describe the current (Ⅰ) - voltage (Ⅴ) characteristics for those planar structures.