Demonstration of Bare Laser-Reduced Graphene Oxide Sensors for Ammonia and Ethanol

In this work, gas sensors using laser-reduced graphene oxide (LrGO) as sensitive layer have been fabricated and studied. The laser-synthetized material was structurally and electrically characterized by means of scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and the four-point contact method. The gas-sensing properties of the samples were studied by their exposition to 10–100 ppm of ethanol and 25–130 ppm of ammonia. The results show that the devices present an electrical response corresponding to a purely resistive behavior up to 100 kHz. It is also demonstrated that the resistivity of the sensing layer increases as the gas concentration increases; being of 0.0402 ± 0.001 [%/ppm] for the case of ammonia and 0.0140 ± 0.001 [%/ppm] for the case of ethanol. These results outperform existing sensors and establish a better balance in terms of simplicity, sensitivity, linearity, and technology sustainability. In summary, this work especially shows the potential of LrGO for low-cost and low-energy gas sensors fabrication.