A CuO–ZnO nanostructured p–n junction sensor for enhanced N-butanol detection

Abstract

Herein, a novel CuO–ZnO nanostructured p–n junction composite is prepared via the hydrothermal method. It is composed of a ZnO two dimensional (2-D) porous nanosheet assembly and leaf-like 2-D CuO nanoplates. Then, its gas sensing performance toward n-butanol is studied. The 2-D/2-D CuO–ZnO composite sensor shows 2.7 times higher sensitivity than that of pure ZnO at 220 °C. Moreover, its response to n-butanol is 3.5–84 times higher than those for other target gases. This reveals an excellent selectivity toward n-butanol. Its detection limit for n-butanol is calculated to be 0.4 ppm, indicating a potential advantage in low concentration detection. The significant enhancement of the composite's sensing performance can be firstly attributed to the p–n junction, which brings electronic sensitization for the composite sensor. Moreover, the porous structure and the open 2-D/2-D heterostructure also contribute to the sensing performance of the composite. These allow the gas molecules to diffuse rapidly, making chemisorption and surface reactions on the p–n junction more easy.