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Cationic Vacancy Mediated Conductivity and Charge Transport in Non‐Stoichiometric Epitaxial BaTi 0.75 Nb 0.25 O 3 Films
Author(s) -
Gao Dong,
Guo Min,
Li Qiang,
Zhang Aihua,
Feng Jiajun,
Qin Minghui,
Fan Zhen,
Chen Deyang,
Zeng Min,
Zhou Guofu,
Lu Xubing,
Liu J.-M.
Publication year - 2019
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201900418
Subject(s) - materials science , vacancy defect , analytical chemistry (journal) , conductivity , electrical resistivity and conductivity , pulsed laser deposition , electron mobility , stoichiometry , charge carrier , fluence , thin film , epitaxy , polaron , condensed matter physics , nanotechnology , optoelectronics , chemistry , ion , electron , physics , engineering , chromatography , layer (electronics) , electrical engineering , organic chemistry , quantum mechanics
High‐quality epitaxial BaTi 0.75 Nb 0.25 O 3 (BNTO) films with controllable Ba/(Nb + Ti) ratio are fabricated by pulsed laser deposition, and a systematic investigation on their conductivity and charge transport behaviors is carried out. The Ba/(Nb + Ti) ratio can be significantly regulated from 0.96 to 0.53 when the laser fluence varies from 0.5 to 2.0 J cm −2 . Resistivity–temperature measurements indicate that all the BNTO films exhibit semiconductor transport behaviors at temperatures from 50 to 400 K. Their conductivity increases monotonically with the decrease in the Ba/(Nb + Ti) ratio. For films with a high Ba/(Nb + Ti) ratio of 0.96, the small polaron (SP) hopping dominates in the temperature range from 200 to 400 K. Nevertheless, the SP hopping can only be observed at temperatures ranging from 285 to 400 K for the films with a Ba/(Nb + Ti) ratio of 0.53, implying that the reduction of Ba vacancy is favorable for SP hopping transport in BNTO films, especially at low temperature. Hall effect measurements indicate a higher carrier mobility observed in the films with lower Ba/(Nb + Ti) ratio, revealing the promotion of carrier mobility by Ba vacancy. The work reveals that cationic vacancy plays an important role in the conductivity and charge transport mechanisms in perovskite oxide materials, such as BNTO films.