Au/Cu2O/ZnO ternary nanocomposite for low concentration NO2 gas sensing at room temperature

Abstract

In this work, the use of a ternary Au/Cu2O/ZnO nanocomposite for low concentration chemiresistive NO2 gas sensing at room temperature is reported. ZnO nanorods are first grown on a Si substrate with pre-patterned electrodes. Cu2O nanocubes and Au nanoparticles are sequentially photoreduced on ZnO nanorods. Under UV-activation, the responses are 26% and 3590% at 5 and 1000 ppb, respectively. The response shows an excellent exponential relationship with the concentration. Below 100 ppb, the response can be considered linearly proportional to the concentration with a sensitivity of 83 ppm−1. The high response of the nanocomposite can be attributed to combined effects of enhanced gas adsorption and efficient charge separation.