ZnO/graphene heterostructure for electrical interaction and application for CO₂ gas sensing

Abstract

Recently, the concentration of 〖CO〗_2, one of the major air pollutants for greenhouse effect, is increasing due to the massive use of fossil fuels. Thus, research about gas sensors for monitoring 〖CO〗_2 gas have performed, and conventional methods have the challenge of requiring complex structures. Thus, research about gas sensors using nanomaterials has been conducted, and graphene-based gas sensors have been actively researched since its extraordinary conductivity. However, there are challenges that the gas absorption site is limited in chemically unstable site. In this study, ZnO/graphene heterostructure to improve the gas absorption area with high conductivity through ZnO on graphene was presented. Each layer acted as a gas adsorption and a carrier conducting layer respectively, and the sensitivity by the thickness of ZnO and the effect of the annealing temperature were evaluated. This work exhibited a sensitivity of 78% at room temperature, and repeatability and selectivity were also studied.

Rationalizing Graphene–ZnO Composites for Gas Sensing via Functionalization with Amines

“…A set of distinguishable wrinkles that were not initially present in GO (Supplementary Materials, Figure S2) but arose upon the amination were observed to protrude through the AmG layer. This was accompanied by the corresponding ED pattern becoming blurred, albeit still presenting as a single set of six distinct (10) and (11) diffraction maxima. This latter fact indicates the predominantly monolayer nature of the synthesized AmG.…”

“…A large number of gas-sensing units with built-in multisensor e-nose devices based on Gr-MO gas-sensitive layers have been developed to date, employing SnO 2 , CeO 2 , and ZnO NPs as the most favored metal oxide representatives [6,8,[11][12][13]. Among the mentioned MO NPs, ZnO ones are the most renowned, owing to their wide bandgap (3.37 eV), significant excitation binding energy (60 meV), and high electron mobility of ca.…”

Design and fabrication of poly-Si/SiO2 Fabry–Perot filter for nondispersive IR CO2 sensors

“…Carbon dioxide (CO 2 ) is the primary cause of global warming, because this gas strongly absorbs heat and has the highest emission rate among the greenhouse gases. 1,2) Therefore, developing cost-effective CO 2 sensors has been attracting great interest because of the demand for real-time CO 2 monitoring [3][4][5] at critical CO 2 emission areas. CO 2 detectors can be mainly classified into metal-oxide, 6,7) acoustic, 8,9) catalytic, 10) and optical [11][12][13] sensors.…”

Sensing Mechanism and Characterization of NO2 Gas Sensors Using Gold-Black NP-Decorated Ga2O3 Nanorod Sensing Membranes

“…In recent years, several materials have been used to fabricate gas sensors. Among them, metal oxide materials, such as zinc oxide (ZnO), , indium oxide (In 2 O 3 ), , tungsten trioxide (WO 3 ), , and gallium oxide (Ga 2 O 3 ), , have garnered significant attention due to their low cost, simple fabrication, small size, and ease manipulation. − In view of their considerable surface-to-volume ratio and more surface gas adsorption sites, nanomaterials and nanostructures are deliberately applied to the gas sensors to improve their performances. − In spite of the fact that homojunctions are formed between nanostructures to improve the sensitivity of gas sensors, , the formation of p–n heterojunctions between nanostructures can effectively promote the sensitivity and the resistance change. − Recently, to further enhance the performances of gas sensors by using an enhanced metal spillover phenomenon, the structures of metal-decorated metal oxide nanorods have been extensively studied and developed. − …”