Articles | Volume 3, issue 2
J. Sens. Sens. Syst., 3, 231–239, 2014

Special issue: Advanced functional materials for environmental monitoring...

J. Sens. Sens. Syst., 3, 231–239, 2014

Regular research article 09 Oct 2014

Regular research article | 09 Oct 2014

Devices based on series-connected Schottky junctions and β-Ga2O3/SiC heterojunctions characterized as hydrogen sensors

S. Nakagomi, K. Yokoyama, and Y. Kokubun S. Nakagomi et al.
  • Faculty of Science and Engineering, Ishinomaki Senshu University Minamisakai, Ishinomaki, Miyagi 986-8580, Japan

Abstract. Field-effect hydrogen gas sensor devices were fabricated with the structure of a series connection between Schottky junctions and β-Ga2O3/6H-SiC heterojunctions. β-Ga2O3 thin films were deposited on n-type and p-type 6H-SiC substrates by gallium evaporation in oxygen plasma. These devices have rectifying properties and were characterized as hydrogen sensors by a Pt electrode. The hydrogen-sensing properties of both devices were measured in the range of 300–500 °C. The Pt/Ga2O3/n-SiC device revealed hydrogen-sensing properties as conventional Schottky diode-type devices. The forward current of the Pt/Ga2O3/p-SiC device was significantly increased under exposure to hydrogen. The behaviors of hydrogen sensing of the devices were explained using band diagrams of the Pt/Ga2O3/SiC structure biased in the forward and reverse directions.