A Hydrogen Gas Sensor Based on Pt/Nanostructured WO3/SiC Schottky Diode

Pt/nanostructured WO3/SiC Schottky diodes were fabricated and applied for hydrogen gas sensing applications. The nanostructured WO3 films were synthesized from tungsten coated SiC substrates via an acid-etching method using a 1.5 M HNO3 solution for 1hr, 2hrs and 3hrs duration. Scanning electron microscopy of the developed films revealed platelet crystals with thicknesses in the order of 2Q-60 nm and lengths between 10Q-700 nm. X-ray diffraction analysis revealed that the rate of oxidation of tungsten increases as the duration of acid-etching increases. The devices were tested towards hydrogen gas balanced in air at different temperatures from 25c to 200c. At 200c, voltage shifts of 0.45 V, 0.93 V and 2.37 V were recorded for devices acid-etched for 1 hr, 2 hrs and 3 hrs duration, respectively upon exposure to 1% hydrogen, under a constant forward bias current of 500 nA