Metal Oxide Nanolayer-Decorated Epitaxial Graphene: A Gas Sensor Study

Abstract

In this manuscript, we explore the sensor properties of epitaxially grown graphene on silicon carbide decorated with nanolayers of CuO, Fe3O4, V2O5, or ZrO2. The sensor devices were investigated in regard to their response towards NH3 as a typical reducing gas and CO, C6H6, CH2O, and NO2 as gases of interest for air quality monitoring. Moreover, the impact of operating temperature, relative humidity, and additional UV irradiation as changes in the sensing environment have been explored towards their impact on sensing properties. Finally, a cross-laboratory study is presented, supporting stable sensor responses, and the final data is merged into a simplified sensor array. This study shows that sensors can be tailored not only by using different materials but also by applying different working conditions, according to the requirements of certain applications. Lastly, a combination of several different sensors into a sensor array leads to a well-performing sensor system that, with further development, could be suitable for several applications where there is no solution on the market today.

Epitaxial Graphene on 4H-SiC (0001) as a Versatile Platform for Materials Growth: Mini-Review

“…Notably, the above-listed examples of sensing applications concern only unmodified pristine epitaxial graphene. At the same time, there is a great deal of interest in epitaxial graphene sensitivity improvement by chemical functionalization [28,29], defect engineering [30,31], and metal oxide nanoparticle decoration [32][33][34].…”

Semiquantitative Classification of Two Oxidizing Gases with Graphene-Based Gas Sensors

“…Similar combinations of graphene with ultra-thin oxide layers have been extensively studied [33][34][35]. A large (almost 100-fold) increase in gas sensitivity was found after the PLD of oxide layers.…”

“…In the chemiresistive sensors built on a large area CVD (chemical vapor deposition) or epitaxial graphene, the highly conducting carbon layer acts as an effective electrical transducer, and the functionalizing layers (or defects, particles, atomic groups) provide receptors for different molecules. The enhanced sensitivity and selectivity of graphene functionalized by pulsed laser deposited layers were previously demonstrated for NO 2 and NH 3 gases and some volatile compounds [33][34][35].…”

“…[35] for PLD functionalized graphene gas sensors. However, with growing sensor temperature, the sensitivity decreases [35], and therefore, 140 • C was chosen as the optimum measurement temperature considering both the sensor speed and response magnitude.…”

Novel Concepts for Graphene-Based Nanomaterials Synthesis for Phenol Removal from Palm Oil Mill Effluent (POME)

“…Further, Rodner et al (2020) prepared graphene layers via epitaxial growth and the silicon sublimation process on the surface of silicon carbide that are decorated with several metal oxide (oxides of copper, vanadium, iron, and zirconium) nanolayers. In this method, the transfer of the graphene lattice is not required as a semi-insulating 4H-silicon carbide substrate [ 73 ]. It is noteworthy that the non-requirement of substrate transfer, the formation of high-quality GO with low defects, and seamless integration are the advantages of the epitaxial growth approach, whereas the involvement of high cost and the formation of multilayered graphene with uncontrollable size are their limitations [ 74 ].…”