Electronic conduction in hot-pressed calcium manganese oxide ceramics

Abstract

The basic concepts of electronic charge transport in materials are crucial for understanding and improving device performances. The electronic conduction is investigated through perfectly dense calcium manganese oxide (CaMnO3) ceramics prepared with simultaneous application of pressure (64 MPa) and temperature (1073 K) using hot-press technique. A proposed model, comprising of grain boundary assisted hopping and trap assisted transport mechanisms agrees well with the acquired current – voltage characteristics in the temperature range of 133–373 K. The estimated decrease in trap charge density with increasing temperature from 1015 cm 3 at 133 K to 109 cm􀀀 3 at 373 K is attributed to the temperature assisted detrapping of the highly localized trap charge carriers, resulting in lesser availability of trapped charges with increasing temperature. An energy band diagram is demonstrated by implementing the broadening and shifting of energetic trap distribution towards deep into the energy gap with increasing temperature observed in the capacitance-frequency measurements and leads to merging of trap states with the conduction band