Non-ohmic conduction in tin dioxide based ceramics with copper addition

Abstract

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 (the barrier height φ) is decreased with an increase in the electric field E. The higher slope of the 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 CuObased intergranular phase.

Electrical properties of SnO2-based varistor ceramics with solid-phase and liquid-phase sintering

“…The high nonlinearity of current-voltage characteristics in the studied ceramics with the nonlinearity coefficient β = 24 − 50 is rather attributed to the grainboundary nature of the conduction mechanism for different SnO 2 -based varistors [12][13][14][15][16][17][18][19][20][21][22][23][24]26]. Electrical conduction in ceramic samples exists across electrically active grain boundaries.…”

“…Oxide ceramics is well known as a material for the preparation of surface acoustic wave devices [1], superconductors [2], current limiters [3], catalysts [4], gas sensors [5], humidity sensors [6][7][8][9][10][11], varistors [12][13][14][15][16][17][18][19] etc. The tin oxide based ceramics has many low electrical resistance grains which are usually separated by the layers with high electrical resistance.…”

“…The tin oxide based ceramics has many low electrical resistance grains which are usually separated by the layers with high electrical resistance. The SnO 2 -based ceramics has non-Ohmic electrical conductivity, which is caused by the potential barriers at the SnO 2 grain boundaries [12][13][14][15][16][17][18][19]. These are double Schottky barriers (two Schottky barriers are connected in opposite directions).…”

HUMIDITY SENSORS BASED ON SnO2 -Co3 O4 -Nb2 O5 -Cr2 O3 SEMICONDUCTOR VARISTOR CERAMICS

“…The high nonlinearity of current-voltage characteristics in SnO 2 -Co 3 O 4 -Nb 2 O 5 -Cr 2 O 3 ceramics and in ceramics with CaO and CuO additions (β = 30 -57) is attributed to the grainboundary nature of conductivity for different tin oxide based varistors [8][9][10][11][12][13][14][15][16][17][18][19]. In these samples the grains are quite conductive but grain-boundary areas are resistive due to the formation of grain-boundary potential barriers during sintering of ceramics in air atmosphere.…”

“…Tin dioxide is well known as a material for the manufacture of gas sensors [1][2][3][4], humidity sensors [3][4][5][6][7] and varistors [8][9][10][11][12][13][14]. The tin oxide based ceramics has non-Ohmic electrical conductivity which is caused by the grain-boundary potential barriers [8 -14].…”