Humidity sensitive electrical properties of a novel ceramic heterocontact structure ZnO/BaPb0.8Bi0.2O3

The humidity dependence of the voltage-current characteristics of nonsymmetrical and symmetrical heterocontacts ZnO/BaPb0.8Bi0.2O3, ZnO/BaPb0.8 Bi0.2O3/ZnO and ZnO/ZnO have been studied at fixed temperature in air with different relative humidity values. Nonlinear characteristics have been observed for all the contacts at any humidity values. The increase in the nonlinearity coefficient for the ZnO/BaPb0.8Bi0.2O3/ZnO contact with respect to the ZnO/ZnO contact, and the voltage-current relationship at forward bias for ZnO/BaPb0.8Bi0.2O3 heterocontacts are attributed to surface states. The increase in relative humidity causes the decrease in the Schottky potential barrier height, thereby resulting in a redistribution of the voltage drop at the heterocontact interface and in the cur rent growth at lower voltages. (C) 1999 Elsevier Science Limited. All rights reserved.