Study of structural and electrical behavior of silicon-carbon nanocomposites via in situ transmission electron microscopy

In this work, we have studied structural and electrical behaviour of Si-incorporated carbon nanostructures (Si-CNS) by performing current-voltage (I-V) measurements using in situ transmission electron microscopy (TEM). The I-V measurement and TEM observation of the corresponding Si-CNS structural transformation during the process was investigated in detail. Structural transformation of Si-CNS was occurred at high electric current flow (~µA), and reach its peak before electrical breakdown damaging the nanostructures. The formation of few layer of graphene from initially amorphous structure were observed with embedded Si particles. The graphitic structures contribute to remarkable improvement of Si-CNS electrical properties depending on the nanostructure shape and Si-C composition. The current increased up to ~74.4 μA for nanofiber, and ~3 mA for nanocone, indicating the improvement of Si-C matrix crystallinity and decrement of Si composition from sublimation due to current-induced Joule heating. In situ heating technique revealed that Si particle begin to agglomerate at ~500°C and the graphitization on the Si surface were occur at > 700 °C in low pressure environment (~10 -5 Pa). The combination of the in situ TEM study can be promising for further understanding of Si-C structural and electrical behaviour towards future development of next-generation electronic and energy applications. • Nanostructure evolution of Si-C nanostructures during applied current flow. • Effect of Si-C composite nanostructure and Si-C composition to electrical properties and current-induced Joule heating is discussed. • Failure of Si-CNS from current breakdown is elucidated. • Graphitization, diffusion path transition and sublimation of Si was substantiated through nanoscale structural study during I-V and heating measurement.