Abstract
The effect of La3+ doping at Ca2+ sites in CaCu3Ti4O12 (CCTO) thin film was investigated. Samples with compositions of Ca(1−3x/2)LaxCu3Ti4O12 (x = 0, 0.05, 0.1, 0.15 and 0.2) were synthesized by sol–gel method. Remarkable non-Ohmic behaviors in all the samples were presented through a semiconductor parameter analyzer. Results showed that with the increase of dopant’s amount, the threshold voltage of CCTO thin films firstly increased and then decreased and the nonlinear coefficient decreases, good thermal and electric stability was found in all samples. XRD results confirmed the single phase formation of all the samples with similar cubic structure of CCTO and characterization with SEM showed a completely opposite trends between the grain size and the threshold voltage. The double Schottky barrier model is used to explain the nonlinearity of CCTO thin films and the relationship between grain size and threshold voltage in the thin films. The presence of Schottky barrier at the grain boundary is confirmed by a linear relationship between ln(J) and E1/2. A possible way is put forward to control the non-Ohmic properties of CCTO thin films based on this research.
Similar content being viewed by others
References
M.A. Subramanian, D. Li, N. Duan et al., High dielectric constant in ACu3Ti4O12 and ACu3Ti3FeO12 phases. J. Solid State Chem. 2(151), 323–325 (2000)
S.Y. Chung, I.D. Kim, S.J.L. Kang, Strong nonlinear current–voltage behavior in perovskite-derivative calcium copper titanate. Nat. Mater. 3(11), 774–778 (2004)
P.R. Bueno, J.A. Varela, E. Longo, SnO2, ZnO and related polycrystalline compound semiconductors: an overview and review on the voltage-dependent resistance (non-ohmic) feature. J. Eur. Ceram. Soc. 28(3), 505–529 (2008)
Y. Huang, D. Shi, Y. Li et al., Effect of holding time on the dielectric properties and non-ohmic behavior of CaCu3Ti4O12 capacitor-varistors. J. Mater. Sci. Mater. Electron. 24(6), 1994–1999 (2013)
P. Lunkenheimer, R. Fichtl, S.G. Ebbinghaus et al., Nonintrinsic origin of the colossal dielectric constants in CaCu3Ti4O12. Phys. Rev. B 70(17), 172102 (2004)
L. Wu, Y. Zhu, S. Park et al., Defect structure of the high-dielectric-constant perovskite CaCu3Ti4O12. Phys. Rev. B 71(1), 014118 (2005)
T.B. Adams, D.C. Sinclair, A.R. West, Characterization of grain boundary impedances in fine-and coarse-grained CaCu3Ti4O12 ceramics. Phys. Rev. B 73(9), 094124 (2006)
G. Zang, J. Zhang, P. Zheng et al., Grain boundary effect on the dielectric properties of CaCu3Ti4O12 ceramics. J. Phys. D Appl. Phys. 38(11), 1824 (2005)
M. Xiao, Q. Hu, Restoration hysteresis effect of nonlinear current–voltage behavior and negative resistance characteristics of sol–gel derived CaCu3Ti4O12 thin films. J. Alloys Compd. 652, 70–73 (2015)
M. Xiao, K. Wang, X. Chenyang et al., Nonlinear current–voltage behavior of CaCu3Ti4O12 thin films derived from sol–gel method. J. Mater. Sci. Mater. Electron. 25(6), 2710–2715 (2014)
C. Chen, C. Wang, T. Ning et al., Enhanced nonlinear current–voltage behavior in Au nanoparticle dispersed CaCu3Ti4O12 composite films. Solid State Commun. 151(19), 1336–1339 (2011)
A.A. Felix, M.O. Orlandi, J.A. Varela, Schottky-type grain boundaries in CCTO ceramics. Solid State Commun. 151(19), 1377–1381 (2011)
P. Fiorenza, R.L. Nigro, V. Raineri et al., High capacitance density by CaCu3Ti4O12 thin films. J. Appl. Phys. 108(7), 074103 (2010)
Y.W. Li, Y.D. Shen, Z.G. Hu et al., Effect of thickness on the dielectric property and nonlinear current–voltage behavior of CaCu3Ti4O12 thin films. Phys. Lett. A 373(27), 2389–2392 (2009)
B.S. Prakash, K.B.R. Varma, Microstructural and dielectric properties of donor doped (La3+) CaCu3Ti4O12 ceramics. J. Mater. Sci. Mater. Electron. 17(11), 899–907 (2006)
J.W. Cahn, The impurity drag effect in grain boundary motion. Acta Metall. 10(62), 789–798 (1962)
G.W. Pabst, L.W. Martin, Y.H. Chu et al., Leakage mechanisms in BiFeO3 thin films. Appl. Phys. Lett. 90(7), 2902 (2007)
Mei Li-Then, Hsiang Hsing-I, Fang Tsang-Tse, Effect of copper-rich secondary phase at the grain boundaries on the varistor properties of CaCu3Ti4O12 ceramics. J. Am. Ceram. Soc. 91(11), 3735–3737 (2008)
R. Bodeux, M. Gervais, J. Wolfman et al., Electrical parameters of Schottky contacts in CaCu3Ti4O12 thin film capacitors. Appl. Phys. A 116(4), 2001–2006 (2014)
Y.H. Lin, J. Cai, M. Li et al., Grain boundary behavior in varistor–capacitor TiO2-rich CaCu3Ti4O12 ceramics. J. Appl. Phys. 103(7), 4111 (2008)
S.A. Pianaro, P.R. Bueno, P. Olivi et al., Effect of Bi2O3 addition on the microstructure and electrical properties of the SnO2.CoO.Nb2O5 varistor system. J. Mater. Sci. Lett. 16(8), 634–638 (1997)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Xiao, M., Sheng, P. Nonlinear current–voltage behavior in La-doped CaCu3Ti4O12 thin films derived from sol–gel method. J Mater Sci: Mater Electron 27, 9483–9488 (2016). https://doi.org/10.1007/s10854-016-4997-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10854-016-4997-0