The development of CuO-ZnO based heterojunction for detection of NO2 gas at room temperature

The goal of the current research was to develop CuO-ZnO heterojunction capable of detecting NO 2 gas at room temperature. Pure CuO and CuO-ZnO composite samples were developed by changing the weight percentage of CuO and ZnO using a simple precipitation method and nominated as CZ0, CZ1, CZ2 and CZ3. Structural, optical and morphological properties of pristine CuO and heterojunctions were studied using XRD, FE-SEM, BET, XPS, FTIR and PL. Investigation of gas sensing properties revealed that the CZ2 sample (20 wt% ZnO) exhibited maximum response of 36.7% to 100 ppm of NO 2 gas at room temperature. The mechanism behind the response of pristine material and CuO-ZnO was explained in detail. The development of p-n heterojunction due to the combination of p-type CuO and n-type ZnO was responsible for the increase in the gas detecting capabilities of the synthesized composite material for detecting NO 2 gas at ambient temperature. Hence, the proposed approach focuses on the design of a cost-effective and sensitive gas sensor that can sense NO 2 gas even at room temperature.