I-V characteristics of the contact interface in a semiconductive BaTiO_3-In composite particle

摘要

The authors previously fabricated semiconductive BaTiO_3-In composite particles. The aggregate could be used as a new positive temperature coefficients (PTC) material, which could be used in arbitrary shapes, differing from the conventional rigid PTC materials. In the composite particle, the interface between the semiconductive BaTiO_3 particles and indium particles plays an important role. In this work I-V characteristics of the interface are investigated in detail. The conclusions obtained in ths research are as follows. (1) The existence of indium particles at the interface between two semiconductive BaTiO_3 particles lowered the electric resistance markedly. This effect was ascribed to the good plasticity and a low value of the work function of indium. (2) In-Ga eutectic liquid alloy and physically vapor-deposited indium film satisfied Ohm's law and did not form a Schottky barrier at the interface with the semiconductive BaTiO_3 material. (3) Physically vapor-deposited gold film formed a high electric resistance at the interface with the semiconductive BaTiO_3 material. This high resistance might be caused by Schottky barrier.