Gas detection using large-size graphene with defects

Abstract

A macroscopic graphene is thermally annealed in oxygen gas, and Raman spectroscopy shows that the number of structural defects increases after thermal annealing. The temperature dependence of resistance is studied in macroscopic graphene with different numbers of structural defects in various gas environments. The temperature dependent slope of normalized resistance is independent of the number of structural defects and is small in the gas environment of heavier molecules. Following the temperature dependent slopes of normalized resistance, one can identify the molecule mass of the environmental gas. The temperature dependence of thermal electric power is sensitive to the quantity of the structural defects.