Hierarchical Sphere-Like ZnO–CuO Grown in a Controlled Boundary Layer for High-Performance H2S Sensing

• Published in: Journal of electronic materials 2021-09, Vol.50 (9), p.5168-5176
• Main Authors: Kamalianfar, Ahmad, Naseri, Mammoud, Abdala, Ahmed A., Jahromi, Siamak Pilban
• Format: Article
• Language: English
• Subjects: Boundary layers; Characterization and Evaluation of Materials; Chemical synthesis; Chemistry and Materials Science; Copper oxides; Electronics and Microelectronics; Gas flow; Heterojunctions; Hydrogen sulfide; Instrumentation; Materials Science; Metal oxide semiconductors; Morphology; Nanoparticles; Nanostructured materials; Nanowires; Optical and Electronic Materials; Original Research Article; P-n junctions; Physical vapor deposition; Recovery time; Response time; Sensors; Silicon; Silicon substrates; Solid State Physics; Spheres; Zinc oxide; Zinc oxides
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-021-09005-4

A highly sensitive sensor for hydrogen sulfide based on a p – n junction between metal-oxide semiconductors is reported herein. Uniform ZnO–CuO hollow spheres were synthesized by a combination of chemical and physical methods. To deposit a uniform ZnO layer, the silicon substrate was tilted from 0° to 40° relative to the gas flow direction during the growth process. Next, a low concentration of CuO nanoparticles was decorated onto the ZnO nano/microstructure using physical vapor deposition (PVD). The ZnO–CuO heterojunction sensor showed a remarkable response of 112 at 100 ppm H 2 S and 158°C. The response time and recovery time were calculated to be 8 s and 35 s, respectively. The response to H 2 S concentration increases of 100 ppm was as high as 3.5 times compared with ZnO alone. Finally, a sensing mechanism is proposed and discussed.