Hydrogen‐Induced Semiconductor Transformation of Lead Zirconate Titanate Ferroelectric Ceramics

Abstract

Semiconductor transformation of lead zirconate titanate (PZT)‐5H ferroelectric ceramics induced by hydrogen has been investigated. The results showed that hydrogen caused the PZT‐5H ferroelectric ceramics to transform from a yellow insulator into a black n‐type semiconductor, and the leakage current and carrier concentration increased but the resistivity decreased with increasing hydrogen concentration. During charging in H2 at a temperature higher than the Curie point, hydrogen would restrain the PZT‐5H ferroelectric ceramics to transform from cubic into tetragonal phase, resulting in the disappearance of ferroelectricity at room temperature. Charging at a temperature below the Curie point, however, did not change the crystal structure of the tetragonal ferroelectric ceramics. The properties and color of PZT‐5H ferroelectric ceramics were restored after outgassing at a high temperature.

Hydrogen in Ferroelectrics

“…The semiconductorization of ferroelectric ceramics by hydrogen can be restored by outgassing. For example, after outgassing of hydrogen at a temperature higher than 400 °C, the hydrogenated PZT restores an insulator, as shown in Figure 7b (Huang et al, 2007). A very few hydrogen can lower the resistivity of PZT from 10 13 Ω·cm to 10 8 Ω·cm.…”

“…A very few hydrogen can lower the resistivity of PZT from 10 13 Ω·cm to 10 8 Ω·cm. carrier concentration increases rapidly with the raise of hydrogen concentration (Huang et al, 2007). Hall effect measurements show that PZT ceramics change into n-type semiconductor after hydrogen charging (Huang et al, 2007).…”

“…Because that many ferroelectric ceramics, such as PZT and BaTiO 3 , are excellent insulator against current, they are used to electric industry as capacitor. Hydrogen can increase leakage current and induce the insulator to a semiconductor (Huang et al, 2007& Chen et al, 2011. Ferroelectric materials, especially its single crystals, have been widely used in optical devices because of its special optical properties such as photorefractive effect and nonlinear optical effect.…”

Hydrogen interstitial defects in acceptor-type CuO-doped PbTiO3—Uptake and dissolution of water vapor and formation of (CuTi″−(OH)O•)′ defect complexes

“…7 Correspondingly, the variation from V O Þ Â defect complexes will be present. These contribute to the electrical conductivity by means of an ionic charge-transport mechanism…”

“…[4][5][6] Second, in devices fabricated from "bulk" piezoelectrics that are processed under ambient atmosphere, humidity can increase the leakage current, inducing an insulator-semiconductor transition. [7][8][9][10][11] To investigate the interplay between hydrogen-related defects and defects resulting from aliovalent acceptor doping, CuO-doped PbTiO 3 has been investigated. As a sensitive spectroscopic tool, electron paramagnetic resonance (EPR) has already been providing detailed information, 12,13 in particular, on the defect structure at the first coordination sphere.…”