Ambient-temperature incorporated hydrogen in Nb:SrTiO3 single crystals

Electrolysis of water has been implemented to inject hydrogen into the SrTiO3 single crystal doped with 1 wt % of Nb. Direct evidence of OH− group formation in the Nb:SrTiO3 single crystal has been obtained by Fourier-transform infrared (FTIR) analysis, showing an intensity increase of the absorption at a wave number of about 3500 cm−1. FTIR analysis also revealed lattice relaxation due to hydrogen doping. High-resolution x-ray diffraction (XRD) analysis further illustrated lattice expansion, as evidenced by the left shift of the SrTiO3 (200) peak for the hydrogen doped sample. The decrease in the XRD rocking curve linewidth of this (200) peak for the hydrogen-doped sample suggested that hydrogen doping relaxed the local constraints in the crystal. In contrast to the usual great increase in conductivity of insulating perovskite oxides by hydrogen doping, an obvious decrease in conductivity of the highly conductive Nb:SrTiO3 single crystal was observed after hydrogen doping.