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6
GaN-Based Metal/
Insulator/Semiconductor-
Type Schottky
Hydrogen Sensors
Ching-Ting Lee, Hsin-Ying Lee, and Li-Ren Lou
6.1 INTRODUCTION
Hydrogen (H
2
) gas has many interesting and useful properties and has been widely
used as hydrogenating and reducing agents in numerous industrial branches, such as
petroleum, chemical, metallurgical, and foodstuff industries. It is also used in power
stations as a coolant in electric generators. Nowadays, environmental pollution has
become a major issue. Hydrogen, as one of potentially clean energy sources, has
attracted intensive attention. Hydrogen gas is expected to be one of the principal
energy sources in ...