High-Performance Sensor Based on Thin-Film Metallic Glass/Ultra-nanocrystalline Diamond/ZnO Nanorod Heterostructures for Detection of Hydrogen Gas at Room Temperature

This article outlines a novel material to enable the detection of hydrogen gas. The material combines thin-film metallic glass (TFMG), ultra-nanocrystalline diamond (UNCD), and ZnO nanorods (ZNRs) and can be used as a device for effective hydrogen gas sensing. Three sensors were fabricated by using combinations of pure ZNRs (Z), UNCD/ZNRs (DZ), and TFMG/UNCD/ZNRs (MDZ). The MDZ device exhibited a performance superior to the other configurations, with a sensing response of 34 % under very low hydrogen gas concentrations (10 ppm) at room temperature. Remarkably, the MDZ-based sensor exhibits an ultra-high sensitivity of 60.5 % under 500 ppm H-2. The MDZ sensor proved very fast in terms of response time (20 s) and recovery time (35 s). In terms of selectivity, the sensors were particularly suited to hydrogen gas. The sensor achieved the same response performance even after two months, thereby demonstrating the superior stability. It is postulated that the superior performance of MDZ can be attributed to defect-related adsorption as well as charge carrier density. This paper also discusses the respective energy band models of these heterostructures and also the interface effect on the gas sensing enhancements. The results indicate that the proposed hybrid TFMG/UNCD/ZNRs nanostructures could be utilized as high-performance hydrogen gas sensors.