Hydrogen-sensitive amorphous ferroelectric thin film capacitive devices

Amorphous ferroelectric thin film capacitive gas sensors with a largely improved sensitivity to hydrogen have been developed recently, showing a great promising potential for the next generation hydrogen detection technology. This review presents an overall picture of amorphous ferroelectric thin film hydrogen gas sensors, starting from the hydrogen-damage phenomena of ferroelectric thin films during the forming gas annealing (FGA) process. It stresses on the correlation among processing, microstructural evolution and electric properties of amorphous ferroelectric thin films for fabrication concerns. An attempt is made to detail the hydrogen sensitivity and transient response of various prototype capacitive devices with respect to the instinct of the films and the hydrogen kinetic processes in the Pd/ferroelectric heterostructure. Recent advances on the hydrogen-damage mechanism of ferroelectric thin films and the hydrogen interface-blocking model for amorphous ferroelectric gas sensors are also described.