Negative thermal expansion coefficient of graphene measured by Raman spectroscopy

Nano Lett. 2011 Aug 10;11(8):3227-31. doi: 10.1021/nl201488g. Epub 2011 Jul 11.

Abstract

The thermal expansion coefficient (TEC) of single-layer graphene is estimated with temperature-dependent Raman spectroscopy in the temperature range between 200 and 400 K. It is found to be strongly dependent on temperature but remains negative in the whole temperature range with a room temperature value of (-8.0 ± 0.7) × 10(-6) K(-1). The strain caused by the TEC mismatch between graphene and the substrate plays a crucial role in determining the physical properties of graphene, and hence its effect must be accounted for in the interpretation of experimental data taken at cryogenic or elevated temperatures.