| AVS 57th International Symposium & Exhibition | |
| Graphene Focus Topic | Wednesday Sessions |
| Session GR+EM+MS+TF+MI-WeM |
| Session: | Graphene and Carbon-based Devices |
| Presenter: | S.W. Howell, Sandia National Laboratories |
| Authors: | S.W. Howell, Sandia National Laboratories L.B. Biedermann, Sandia National Laboratories T. Ohta, Sandia National Laboratories T.E. Beechem, Sandia National Laboratories W. Pan, Sandia National Laboratories A.J. Ross, Sandia National Laboratories D.C. Trotter, Sandia National Laboratories |
| Correspondent: | Click to Email |
In this paper, we present our recent advancements in electrostatically transferring epitaxial graphene (EG) from SiC(0001) and SiC(000-1) to arbitrary glass substrates (including Pyrex). We will compare the electronic properties of electrostatically transferred EG and nominally-equivalent as-grown EG on SiC. These properties are measured using magnetoresistive, four-probe, and field effect transistor geometries. We feel this is a potential enabling technology for integration of graphene with structured and electronically-active substrates, such as MEMS and CMOS.
CVD-grown graphene on Cu has attracted wide interest since it can be readily transferred to arbitrary substrates. However, CVD-grown graphene has been shown to have lower mobilities and smaller domain sizes than EG. EG is difficult to transfer to arbitrary substrates. Currently two techniques exist to transfer EG – a gold/polymer film handle and thermal tape exfoliation [1,2]. While transfer is possible with these techniques, problems exist including contamination and damage, as measured by Raman spectroscopy.
To overcome the issues with the above mentioned transfer techniques, we have developed a technique capable of electrostatically transferring both patterned and chip-scale regions of EG to arbitrary glass substrates. We start with high-quality graphene (mobility 14,000 cm2/Vs and domains >100 um2) grown using an Ar-mediated approach [3,4]. In electrostatic graphene transfer, a large electric field is applied between the donor graphene sample (anode) and the acceptor insulating substrate (cathode). This strong electrostatic force deposits graphene on the insulating surface. Electrostatic transfer of EG is a clean technique which, unlike other EG transfer methods, does not contaminate the graphene with adhesive residue or gold contaminates. Both few-layer graphene from SiC(000-1) and monolayer graphene from SiC(0001) have been transferred using this technique.
Our initial attempts at EG transfer have been extensively characterized with Raman spectroscopy and atomic force microscopy. Raman spectroscopy shows that the inherent strain in EG has been partially relaxed. Furthermore, a defect peak (D peak) is frequently not seen in the transferred graphene indicating that the procedure does not significantly damage the graphene film.
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.
[1] D. Lee et al. Nano Lett. 8, 4320 (2008)
[2] S. Unarunotai et al. APL 95, 202101 (2009)
[3] W. Pan et al. submitted to APL (2010)
[4] K. Emtsev et al. Nature Mat. 8, 203 (2009)