Polymer Assisted Transfer of Graphene onto Semiconductor Substrates

Abstract: Since first being isolated in 2004, Graphene has been researched heavily because of its unique properties. Recently, interest has grown in graphene/semiconductor heterostructures. In this work, the transfer of graphene through the use of cellulose acetate butyrate (CAB) polymer is studied. CAB assisted transfer of graphene to indium arsenide (InAs) (111)B and undoped gallium arsenide (GaAs) (110) wafers is performed, and the CAB is removed by submerging the samples in acetone. The resulting graphene/semiconductor heterostructures are examined using optical microscopy and scanning tunneling microscopy (STM). Optical microscopy revealed that a significant amount of polymer residues remained on the surfaces of the semiconductors following the treatment with acetone, although these residues were only apparent in the locations of the transfers. STM images of the clean areas of the InAs wafers confirmed that minimal polymer residues were present outside the transfer site. Using STM measurements from one of these areas, the interplanar distance for InAs(111)B planes was estimated to be 3.56 Å, very nearly the value of 3.50 Å that is predicted by theory. STM at the locations of the transfers had drastically reduced image quality, likely due to polymer residues adhering to the STM tip. Future studies are recommended involving the use of polymethyl-methacrylate (PMMA) in place of CAB or using ethyl acetate to dissolve the CAB before treating the samples with acetone.