Enhanced Performance Enabled Room Temperature Hydrogen Detecting with Pd-Ti/ZnO SB-TFT

An efficiently sensitive hydrogen sensor based on Pd-Ti/n-ZnO Schottky barrier thin-film transistor (SB-TFT) has been developed at room temperature (RT) using RF sputtering and optical lithography without associating any heating element. The developed sensor reduces device design complexities and power consumption considerably. Increase in drain current has been observed under H
2
exposure which can be attributed to the Schottky barrier height reduction. In this experimental investigation, for 500 ppm to 4500 ppm H
2
concentration range, the sensor revealed RT detection with a maximum response of 69.78% (for 4500 ppm) with 26/83 s (for 4500 ppm) and 80/50 s (for 500 ppm) response/recovery time. The associated hydrogen sensing mechanism has been demonstrated. Apart from detailing the structural and chemical state analysis of the fabricated film, electrical properties of the fabricated device have also been elucidated in this work. Sensing response in presence of other industrially relevant gas species have been investigated including other parameters such as repeatability, response in humid environment (0-10%, 40% and 80%), hysteresis effect and stability.