Temperature and frequency dependent conductive behavior study on polymer-derived SiBCN ceramics

Conductive behavior research is vital for in-depth understanding the conductive capabilities of materials as well as promoting the development of their applications in fields such as electronics, energy and sensing. In the article, the AC conductive behavior was systematically evaluated for polymer-derived SiBCN ceramics by complex impedance spectroscopy and electrical modulus methods. The results suggest that SiBCN ceramics have a frequency-independent conductivity at low frequencies, whereas it exhibits a relaxation process with increasing frequency at high frequencies. In addition, the SiBCN ceramics follow the electron hopping conductive mechanism in both low and high-frequency bands over the testing temperature range. By considering the relationship between the prefactor sigma(0) and T-0, the conductive mechanism is revealed to be the band-tailed state hopping instead of the variable range hopping. It is worth noting that although the material has the same conductive mechanism at various testing temperatures, hopping is mainly controlled by the matrix phase at low frequencies; while at high frequencies, hopping is dominated by free carbon phase. Our results provide the underlying insights needed to guide the design of amorphous SiBCN ceramics for applications in electrically relevant fields.