Effect of Thermal Initiator Concentration on the Electrical Behavior of Polymer-Derived Amorphous Silicon Carbonitrides

The electric conductivity of polymer-derived silicon carbonitrides made from a polysilazane modified with different amounts of thermal initiator is measured at room temperature. It is found that the thermal initiator has a significant effect on the electric conductivity, which first increases and then decreases with increasing thermal initiator concentration. The highly conductive sample exhibits a very high piezoresistive coefficient and weak temperature dependence as compared with the low conductive samples. The microstructures of the materials are characterized using a Raman spectroscope. Based on these results, two conducting mechanisms are identified: the highly conductive sample is dominated by the tunneling-percolation mechanism, while the low conductive samples are dominated by matrix phases. The effect of the thermal initiator on the development of the microstructures of the materials is discussed.