Study of a GaN Schottky diode based hydrogen sensor with a hydrogen peroxide oxidation approach and platinum catalytic metal

A platinum (Pt) catalytic metal and a hydrogen peroxide oxidation approach are utilized to fabricate a hydrogen sensor based on a GaN Schottky diode. The presence of a gallium oxide dielectric layer between the Pt metal and the GaN surface can increase the adsorption sites for dissociated hydrogen species, thereby improving the related sensing ability towards hydrogen gas. Experimentally, under introduced 1% hydrogen/air gas, the studied device shows a high sensing response ratio of 1.03 x 10(5) at 300 K. In addition, the lowest detecting level of 1 ppm hydrogen at 300 K is obtained. This device also exhibits good high-temperature durability (>= 573 K) and a high sensing speed. The response (recovery) time constant at 300 K is only 74 (103) sec even under a very low hydrogen concentration of 1 ppm; these time constant values are much smaller than those of palladium metal-based sensors. Under the 1% hydrogen/air, the response (recovery) time constant at 300 K is drastically reduced to 15 (19) sec. Furthermore, in order to improve the feasibility of transmitting the sensing data, the concept of linear differentiation method is employed to eliminate redundant data. The simulation result shows that the average of the reduced ratios can achieve 77.88%. Therefore, this Schottky diode device not only shows promise to detect hydrogen gas, but also can be utilized effectively in the transmission of sensing data. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.