Development of Noble Metal-Gate TiO_2 Schottky Diode DH sensor

Research Project

Project/Area Number	05555186
Research Category	Grant-in-Aid for Developmental Scientific Research (B)
Allocation Type	Single-year Grants
Research Field	Material processing/treatments
Research Institution	TOHOKU UNIVERSITY
Principal Investigator	SUGIMOTO Katsuhisa Tohoku University, Engineering, Professor, 工学部, 教授 (80005397)
Co-Investigator(Kenkyū-buntansha)	AKAO Noboru Tohoku University, Engineering, Research Assistant, 工学部, 助手 (80222503) HARA Nobuyoshi Tohoku University, Engineering, Associate Professor, 工学部, 助教授 (40111257)
Project Period (FY)	1993 – 1994
Project Status	Completed (Fiscal Year 1994)
Budget Amount *help	¥6,500,000 (Direct Cost: ¥6,500,000) Fiscal Year 1994: ¥1,000,000 (Direct Cost: ¥1,000,000) Fiscal Year 1993: ¥5,500,000 (Direct Cost: ¥5,500,000)
Keywords	Dissolved hydrogen sensor / TiO_2 single crystal / Noble metal base alloy / High-temperature and high-pressure solution / Ion beam sputtering
Research Abstract	An application of hydrogen-sensitive metal-gate Schottky barrier diodes to dissolved hydrogen (DH) sensors was examined. Single crystals of Nb_2O_5-doped TiO_2 and thin films of Pd-base alloy (Pd-Ag, Pd-Au, Pd-Pt) were used as a semiconductor and a catalytic metal-gate of diodes, respectively. The DH response of the diodes was first examined in aqueous solutions with various DH concentrations at 298K.It was found that Pd-30-40at%Ag alloy-gate diodes showed a high sensitivity to DH over a wide concentration range. They did not suffer from hydrogen embrittlement at 298K and had a good corrosion resistance at elevated temperatures. Linear relationships between the response voltage of Pd-30-40at%Ag diodes and the DH concentration of solutions were found at every temperatures examined (1298-573K) . The sensitivities of the diodes to pH were less than 10% of their sensitivities to DH.The diodes showed good long-term stability, while their DH response rate decreased after prolonged exposure in high-temperature solutions.