II-VI Semiconductor-based Thin-Film Transistor Sensor for Room Temperature Hydrogen Detection From Idea to Product Development

 Implementing gas sensors incorporating nanoelectronic devices to detect pollution and improve the safety control of industrial, medical, and domestic sectors has opened up a novel world with immense interest. As a promising renewable energy carrier and a potential replacement for fossil fuels, there is the paramount importance of hydrogen gas storage at extensive facilities worldwide. The sustainable production of hydrogen is increasing owing to its enormous energy per mass of any fuel. Nevertheless, due to its extreme flammability, simple and highly accurate sensors with promising sensing materials are required to detect the slightest traces of timely leak detection for developing a hydrogen economy. Various hydrogen detectors already exist, but expensive cost, large size, sluggish response, and high temperature limit their potential for widespread applications. The integral objective of the present chapter is to focus on a systematic investigation of Pd-Ti/ZnO Schottky TFT-based room temperature hydrogen sensors excluding any heating element. With high chemical and thermal stability, ZnO is a promising candidate for sensors in a hazardous atmosphere. The developed sensor exhibited room temperature detection with a maximum response of 33.8% to 4500 ppm H2 in dry air. The selectivity analysis toward H2 in the presence of other reducing and oxidizing gas species has also been investigated to ensure the real-time applicability of the sensor. Reliable operation of the sensor in a wide range of 500 ppm to 4500 ppm H2 has been confirmed from the linear behavior of the sensor. The hydrogen sensing mechanism of the proposed sensor in terms of Schottky barrier height reduction at the interface of Pd-Ti/ZnO has also been detailed in this chapter. Room temperature detection of the hydrogen sensor presented here competes favorably with the existing studies. This study can be extended in exploring new routes to realize hydrogen sensing applications at room temperature for commercialization with precise control over film thickness and target gas concentrations. 

Keywords: Hysteresis, Room temperature, Pd-Ti/ZnO Schottky TFT, hydrogen sensor, Repeatability, Selectivity, Reproducibility.