Variable temperature Raman microscopy as a nanometrology tool for graphene layers and graphene-based devices

Raman microscopy of graphene was carried out over the temperature range from 83to373K. The number of layers was independently confirmed by the quantum Hall measurements and atomic force microscopy. The values of the temperature coefficients for the G and 2D-band frequencies extracted from Raman spectra of the single-layer graphene are −(1.6±0.2)×10−2cm−1∕K and −(3.4±0.4)×10−2cm−1∕K, respectively. The G peak temperature coefficients of the bilayer graphene and bulk graphite are −(1.5±0.06)×10−2cm−1∕K and −(1.1±0.04)×10−2cm−1∕K, respectively. The results are important for the application of Raman microscopy as a nanometrology tool for the graphene-based devices operating at various temperatures.