Effect of free carbon content changed by divinylbenzene on the conductivity of SiCN ceramic

SiCN ceramic is a candidate material for high-temperature sensors because of its stability and semiconductor characteristics at high temperatures. The free carbon content within the SiCN ceramics is a main factor that affects its conductivity. This study adjusted the free carbon content inside amorphous SiCN by adding divinylbenzene into the precursor. The electrical properties of SiCN ceramics with different free carbon contents were explored using ultraviolet fluorescence spectrum and temperature-resistant experiments. The results showed that with the increase of divinylbenzene from 0 to 20%, the conductivity of SiCN ceramics at room temperature increases from 2.77 × 10 −9  to 3.66 × 10 −4  S/cm, and the forbidden bandwidth decreases from 3.81 to 2.25 eV. At the same time, the increase of divinylbenzene content would promote the hybridization extent of free carbon from sp 3 to sp 2  and improve the degree of order. This work could pave the way for applying amorphous SiCN serving as temperature sensors.