Development of p-type zinc oxide nanorods on zirconium-based metallic glass nanotube arrays by facile hydrothermal method for gas sensing applications

In this study, p-type zinc oxide (ZnO) nanorods grown on zirconium-based metallic glass nanotube arrays were developed for hydrogen gas sensing applications. Heterogeneous zirconium-based metallic glass nanotube arrays were synthesized by sputter deposition of metallic glass (Zr60Cu25Al10Ni5) over contact-hole arrays created using a photoresist template (diameter, 2 µm). To provide nucleation sites for the growth of nanorods inside the zirconium-based metallic glass nanotube arrays, a ZnO seed layer was deposited. ZnO nanorods were grown using the hydrothermal method. The developed p-type ZnO nanorods were systematically characterized, and the reason behind the change from n-type ZnO to p-type ZnO was explained based on experimental findings. The sample was then sputtered with Pt electrodes to obtain a hydrogen sensing device. The fabricated zirconium-based metallic glass nanotube arrays with ZnO nanorods (Zr-ZnO nanorods) exhibited outstanding hydrogen gas sensing property of 28% sensor response at room temperature. Besides, the H2 gas sensing performance of the developed sensor is better than that of the ZnO-based H2 gas sensors in the open literatures. It also presented excellent cyclic and long-term stability, which is crucial for practical applications. The preparation method is also easy, fast, and at low temperatures. Therefore, this study paves the way for the development of p-type ZnO with potential applications in various areas; the developed sensor can be used for environmental remediation and monitoring.