Non-ohmic properties of CaCu3Ti4O12 thin films deposited By RF-sputtering

作者：Foschini C R; Hangai B; Cavalcante C S; Simoes A Z^*; Cilense M; Longo E

来源：Journal of Materials Science: Materials in Electronics , 2017, 28(20): 15685-15693.

DOI：10.1007/s10854-017-7458-5

Calcium copper titanate (CaCu3Ti4O12, CCTO), thin films with polycrystalline nature have been deposited by RF sputtering on Pt/Ti/SiO2/Si (100) substrates at a room temperature followed by annealing at 600 degrees C for 2 h in a conventional furnace. The CCTO thin film present a cubic structure with lattice parameter a = 7.379 +/- 0.001 angstrom free of secondary phases. Dielectric spectroscopy was employed to examine the polycrystalline behaviour of CCTO material and the mechanisms responsible for the barrier-layer capacitances associated with Schottky-type barriers and the non-Ohmic properties. The film presents an electric breakdown field (E-b = 203 V cm(-1)) and then nonlinear coefficient (alpha = 6), which is even lower than that of the ZnO and SnO2 based varistors The observed electrical features of CCTO thin films are highly dependent on the [CaO12], [CaO4], [CuO11], [CuO11Vox] and [TiO5 center dot V-O(center dot)] clusters.

• 出版日期2017-10