|About this Abstract
||2010 Electronic Materials Conference
||TMS 2010 Electronic Materials Conference
||M8, Comparison of Graphene Thickness Determination for MBE Grown Graphene on SiC Using Raman, XPS, and TEM
||David H Tomich, John Boeckl, Jeongho Park, John Hoelscher, Larry Grazulis, Kurt Eyink, Chip Claflin, William Mitchel
|On-Site Speaker (Planned)
||David H Tomich
Graphene’s exponential rise in interest since its isolation by Geim et al. in 2004 has led to a plethora of publications using different techniques to determine the number of graphene layers present. The techniques range from the very quick and simple optical interference microscopy for exfoliated graphene on SiO2/Si substrate to the tedious and time consuming sample preparation for Transmission Electron Microscopy (TEM) for sublimation grown graphene on SiC. Raman spectroscopy is one of the most reported tools used to determine graphene thickness due to its ease of use, non-destructive nature and wide availability. Raman spectroscopy has been used extensively over the past few decades to study carbon based materials, so the study of this perfect two dimensional form of carbon with Raman is a natural application. Several methods have been used to glean information from the Raman spectrum to relate the number of layers or quality to the electronic properties. We have examined several of these methodologies along with photoelectron spectroscopy and TEM in order to determine an accurate, consistent and rapid process to guide our graphene growth experiments. We have examined x-ray photoelectron spectra (XPS), confocal Raman spectra and TEM images from portions of the same sample in an effort to determine the relative accuracies of these techniques. Growths were conducted in an EPI (Veeco) 930 MBE tool with a modified graphite heater to facilitate growth temperatures up to 1600°C. Films were grown on the chemical-mechanical polished (CMP) Si-face of 6H SiC semi-insulating substrates diced into 10 x 10 mm2 samples. Atomic force microscopy images of the growths indicate good step flow growth with RMS roughness less than 5 nm over 20 x 20 µm2.