Monitoring the low doping regime in graphene using Raman 2D peak-splits: Comparison of gated Raman and transport measurements
Files
First author draft
Date
2019-08-28
DOI
Authors
Chen, Zhuofa
Ullberg, Nathan
Vutukuru, Mounika
Barton, David
Swan, Anna
Version
OA Version
First author draft
Citation
Zhuofa Chen, Nathan Ullberg, Mounika Vutukuru, David Barton, Anna Swan. 2019. "Monitoring the low doping regime in graphene using Raman 2D peak-splits: Comparison of gated Raman and transport measurements." ArXiv, Volume arXiv:1908.10961 [physics.app-ph], https://arxiv.org/abs/1908.10961
Abstract
Avoiding charge density fluctuations and impurities in graphene is vital for high-quality graphene-based devices. Traditional characterization methods require device fabrication and electrical transport measurements, which are labor-intensive and time-consuming. Existing optical methods using Raman spectroscopy only work for doping levels higher than ~10^12 cm^-2. Here, we propose an optical method using Raman 2D peak-splitting (split between the Raman 2D1 and 2D2 peaks at low doping levels). Electrostatically gated Raman measurements combined with transport measurements were used to correlate the 2D peak-split with the charge density on graphene with high precision (2x10^10 cm^-2 per 2D peak-split wavenumber). We found that the Raman 2D peak-split has a strong correlation with the charge density at low doping levels, and that a lower charge density results in a larger 2D peak-split. Our work provides a simple and non-invasive optical method to quantify the doping level of graphene from 10^10 cm^-2 to 10^12 cm^-2, two orders of magnitude higher precision than previously reported optical methods. This method provides a platform for estimating the doping level and quality of graphene before fabricating graphene devices