Oxygen Desorption by Graphene-Based Carbon Films Obtained Through Sublimation

Background: Nanocarbon materials are known as highly sensitive gas sensors when compared to common solid-state sensors. This manuscript discusses graphene-based carbon films as materials for a gas sensor operating at near room temperature. Methods: The structural characteristics of graphene-based carbon films on In2O3- and ITO- coated substrates were studied by confocal laser microscopy, SEM, and Raman spectroscopy. Microwave conductivity was measured by using a λ/4 coaxial resonator based on a symmetric two-wire line in the frequency range 0.65 - 1.2 GHz and the temperature range 290-360 K. Results: The results obtained showed that films on In2O3 - and ITO-coated substrates desorb oxygen from the various structural levels of graphene-based carbon, such as crystalline contacts between globular nanoparticles and distorted graphene fragments. A correlation between the size of nanoparticles in films and the desorption temperature was also revealed. Conclusion: Our studies have shown that thin films of natural graphene-based carbon are promising as gas sensors. The possibility of varying characteristic oxygen desorption temperatures on different substrates is discussed.