Electron Transport In Polymer-Derived Amorphous Silicon Oxycarbonitride Ceramics

The electron transport behavior of polymer-derived amorphous silicon oxycarbonitride ceramics is studied by measuring their temperature-dependent electrical conductivities. The experimental results are analyzed using theoretical models. The results reveal that the materials exhibit three conduction mechanisms: conduction in extended states, conduction in band tails, and conduction in localized states. Particularly, it is found that in a low-temperature regime, the conduction of the materials follows a band tail hopping mechanism, rather than the previously assumed variable range hopping mechanism. The results also reveal that energy gaps such as E C-E F and E C-E A decrease with increasing pyrolysis temperature. © 2009 The American Ceramic Society