Multifunctional dumbbell-shaped ZnO based temperature-dependent UV photodetection and selective H2 gas detection

Abstract In this article, a single step, chemically synthesized dumbbell-shaped ZnO microcrystal has been utilized to fabricate UV photodetectors and highly selective H2 gas sensors. The structural, morphological, chemical states and optical properties were investigated via using various characterization tools. The dumbbell-shaped morphology acquires 1.2–1.4 μm length and diameters of 300–400 nm respectively. The temperature-dependent photodetection and gas sensing characteristics has been studied in the temperature range 298.15–433.15 K respectively. The maximum relative change in photoresponse and gas sensor response has been found at 358.15 K. The rise time and fall time have been reduced from ~2.4 sec to ~1.0 sec and ~3.1 sec–~2.2 sec respectively in the applied temperature range. Such behavior is attributed to the increasing desorption rate with a higher operating temperature. The maximum sensor response towards H2 was found to be ~20% for 100 ppm concentration at an operating temperature of 358.15 K.