Electrodeposition of ZnO nanorods onto GaN towards enhanced H2S sensing

Abstract Zinc oxide nanorods (ZnO NRs) were grown on gallium nitride (GaN) substrates by electrodeposition. HRTEM and XRD analyses were performed to determine crystalline structure. Single crystal ZnO NRs with an average size of 240 nm were grown along the c-axis direction. The resulting H2S sensors based on ZnO NRs/GaN displayed excellent selectivity and response, particularly in the concentration range of 1–50 ppm of H2S. In the concentration of 50 ppm H2S, a sensing response time of 82 s and a recovery time as low as 48 s can be achieved at 240 °C. In addition to ZnO NRs forming porous network channels for gas diffusion in and out, the H2S-sensing performance of ZnO NRs/GaN heterojunctions could be attributed to the enhanced electron transport and the favorable charge transfer resulting from the excellent transport capability of GaN. The in-situ fabrication of sensing materials makes our sensors extremely attractive in the field of H2S detection.