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Semiconductor Physics, Quantum Electronics & Optoelectronics. 2011. V. 14, N 1. P. 071-076.
Non-ohmic conduction in tin dioxide based ceramics
with copper addition
1Dnipropetrovsk National University, 72, Gagarin Ave., 49010 Dnipropetrovsk, Ukraine
E-mail: alexei_gaponov@ukr.net Abstract.
The current-voltage characteristics and temperature dependences of electrical
conductivity in SnO 2 -Co 3 O 4 -Nb 2 O 5 -Cr 2 O 3 -CuO semiconductor ceramics are studied, and
possible mechanism of non-ohmic conduction in these materials is discussed. Due to
addition of CuO up to 0.5 mol.%, the nonlinearity coefficient is increased up to 75, and
the electric field is decreased down to (at ). It makes CuO
addition useful for the preparation of SnO
1 cm V 3900 − ⋅ 2 cm mA 1 − ⋅
2 -based varistors. It is concluded that the
electrical conduction is controlled by grain-boundary barriers. The activation energy of
electrical conduction (the barrier height φ) is decreased with an increase in the
electric field E. The higher slope of the E dependence at high fields can be related
to a participation of minority carriers (holes). The addition of more than 0.5 mol.% CuO
leads to degradation of the varistor effect due to percolation via quite conductive CuO-
based intergranular phase.
Keywords: non-ohmic conduction, grain boundary, varistor, barrier height, tin dioxide
ceramics.
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