Sputter-Grown Pd-Capped CuO Thin Films for a Highly Sensitive and Selective Hydrogen Gas Sensor

In the present work, hydrogen gas sensing properties of palladium-capped copper oxide (Pd/CuO) thin films have been investigated. The Pd/CuO thin films were deposited on glass substrate for different deposition times (10–30 min) using direct current magnetron sputtering. The Pd/CuO thin films were characterized by x-ray diffraction, field emission scanning electron microscopy, atomic force microscopy and x-ray photoelectron spectroscopy for their structural, morphological and compositional properties, respectively. The Pd/CuO thin film sensor deposited for 10 min presents a remarkable sensing performance with fast response/recovery time of 10 s/50 s for hydrogen gas at a concentration of (1000 ppm) and optimum operating temperature of 300°C. The sensor is observed to be highly selective towards hydrogen (H2) gas compared to the other gases such as carbon monoxide (CO) and ammonia (NH3). The sensor is stable under high humidity conditions (60% RH). The studied Pd/CuO thin film sensor can be used to design a simple and low-cost sensor to detect low concentrations of H2 gas for use in hydrogen-driven industries.