11:45 AM - 12:00 PM
▲ [13a-N306-11] In situ TEM observation of silicon-carbon nanofiber composites structural transformation via joule heat
Keywords:in situ TEM, graphitization, joule heat
Carbon nanostructures (CNS) such as carbon nanotubes (CNTs), carbon nanofibers (CNFs) and graphene attracts much attention owing to their outstanding electrical properties for various application such as electrical wires and electron emission sources. Basically, catalysts were required to synthesize those materials using conventional method like chemical vapor deposition (CVD), arc-discharge and pulse laser deposition. However, the details of the CNS formation were still remained unclear. It is necessary to understand the interaction between carbon and other catalytic materials as it is one of the key-point in order to produce high quality materials in a large scale. In this work, we will demonstrate structural transformation of Si-CNF composite via joule heating through current flow using in situ TEM facilities.
Sample were grown on the edge of graphite foil of 100 µm thickness by co-sputtering the graphite foil and Si plate, using Ar ion irradiation at room temperature1). The basal and working pressures of the chamber were 1 × 10-5 Pa and 5 × 10-2 Pa, respectively. The sample and tungsten (W) nanoprobe were mounted on a special TEM holder, which act as cathode and anode, respectively. The I-V measurements were carried out while observing the structural transformation of the composite CNF using in situ TEM2). Fig. 1(a) shows initial structure of Si-CNF composites which composed of amorphous structures. During I-V measurement, at 776 nA, the current suddenly increase significantly, aligned with structural change of Si-CNF to graphitic structure that have been observed (Fig. 1b) at the same time.
Sample were grown on the edge of graphite foil of 100 µm thickness by co-sputtering the graphite foil and Si plate, using Ar ion irradiation at room temperature1). The basal and working pressures of the chamber were 1 × 10-5 Pa and 5 × 10-2 Pa, respectively. The sample and tungsten (W) nanoprobe were mounted on a special TEM holder, which act as cathode and anode, respectively. The I-V measurements were carried out while observing the structural transformation of the composite CNF using in situ TEM2). Fig. 1(a) shows initial structure of Si-CNF composites which composed of amorphous structures. During I-V measurement, at 776 nA, the current suddenly increase significantly, aligned with structural change of Si-CNF to graphitic structure that have been observed (Fig. 1b) at the same time.