Gan-Based Metal/Insulator/Semiconductor-Type Schottky Hydrogen Sensors

Abstract

This chapter focuses on the important problem of the insulator layer. It introduces the general working principle of Schottky sensors, especially the general role of insulator layers in sensing processes. The chapter demonstrates Gallium Nitride (GaN)-based Metal–Insulator–Semiconductor (MIS) sensors fabricated by using novel deposition method, showing considerably improved sensing performances. It analyzes the roles of the insulator layer of GaN-based MIS Schottky hydrogen sensors. From the aforementioned working mechanisms, it is known that Schottky hydrogen sensors are based on the hydrogen-induced change of the interface state and the properties initiated by metal catalysis reaction, in which the sensors are interface-controlled devices. The chapter discusses the series resistance of MIS hydrogen sensors and its change on exposure to hydrogen-containing ambience. The fabricated sensors exhibited excellent performances, which indicated that two unique methods were very promising for future application in the fabrication of hydrogen sensors.