Large-scale graphitic thin films synthesized on Ni and transferred to insulators: Structural and electronic properties

Helin Cao, Purdue University - Main Campus
Qingkai Yu, University of Houston - Main
Robert Colby, Purdue University
Deepak Pandey, Purdue University - Main Campus
Jie Lian, Rensselaer Polytechnic Institute
Dmitry Zemlyanov, Purdue University - Main Campus
Isaac Childres, Purdue University - Main Campus
V. P. Drachev, Birck Nanotechnology Center, School of Electrical and Computer Engineering, Purdue University
E A. Stach, Birck Nanotechnology Center and School of Materials Engineering, Purdue University
Muhammad Hussain, SEMATECH
Hao Li, University of Missouri - Columbia
Steven S. Pei, University of Houston - Main
Yong P. Chen, Purdue University - Main Campus

Date of this Version



DOI: 10.1063/1.3309018

This document has been peer-reviewed.



We present a comprehensive study of the structural and electronic properties of ultrathin films containing graphene layers synthesized by chemical vapor deposition based surface segregation on polycrystalline Ni foils then transferred onto insulating SiO2/Si substrates. Films of size up to several mm's have been synthesized. Structural characterizations by atomic force microscopy, scanning tunneling microscopy, cross-sectional transmission electron microscopy (XTEM), and Raman spectroscopy confirm that such large-scale graphitic thin films (GTF) contain both thick graphite regions and thin regions of few-layer graphene. The films also contain many wrinkles, with sharply-bent tips and dislocations revealed by XTEM, yielding insights on the growth and buckling processes of the GTF. Measurements on mm-scale back-gated transistor devices fabricated from the transferred GTF show ambipolar field effect with resistance modulation similar to 50% and carrier mobilities reaching similar to 2000 cm(2)/V s. We also demonstrate quantum transport of carriers with phase coherence length over 0.2 mu m from the observation of two-dimensional weak localization in low temperature magnetotransport measurements. Our results show that despite the nonuniformity and surface roughness, such large-scale, flexible thin films can have electronic properties promising for device applications.


Engineering | Nanoscience and Nanotechnology