Skuratovsky I. Electrophysical properties of tin dioxide based ceramics for varistors and humidity sensors

Object of research - effect of deviation from Ohm's law in semiconductor ceramics. Objective - obtaining of the tin dioxide based semiconductor ceramics with high nonlinearity of current-voltage characteristic and determination of the electrophysical properties features of obtained materials with accent on varistor and sensor effects. Methods of research - investigation of the conduction on temperature and humidity variation, optical microscopy, SEM, X-ray diffraction. Varistor ceramics with high deviation from Ohm's law in high electric fields and humidity sensitive in weak fields is obtained. The physical models of varistor and sensor effects are developed. It is shown, what sensitive effect is related to weak decreasing of the grain boundary potential barriers when the humidity increases, and varistor effect is related to strong decreasing of the grain boundary potential barriers when field increases. Combination of humidity sensitive properties and varistor effect could be base to production of devices with combination electric properties - "varistor-sensor".