Amorphous interface layer in thin graphite films grown on the carbon face of SiC

TL;DR

This study uses advanced electron microscopy techniques to characterize an amorphous, carbon-rich interface layer in graphite films grown on SiC, revealing its temperature-dependent formation during thermal decomposition.

Contribution

It provides detailed microscopic analysis of the amorphous interface layer and identifies its composition and temperature-dependent formation mechanism.

Findings

Amorphous layer is carbon-rich and not covering entire interface.

Layer is observed at 1600°C but not at 1500°C.

Formation depends on growth temperature.

Abstract

Cross-sectional transmission electron microscopy (TEM) is used to characterize an amorphous layer observed at the interface in graphite and graphene films grown via thermal decomposition of C-face 4H-SiC. The amorphous layer does not to cover the entire interface, but uniform contiguous regions span microns of cross-sectional interface. Annular dark field scanning transmission electron microscopy (ADF-STEM) images and electron energy loss spectroscopy (EELS) demonstrate that the amorphous layer is a carbon-rich composition of Si/C. The amorphous layer is clearly observed in samples grown at 1600{\deg}C for a range of growth pressures in argon, but not at 1500{\deg}C, suggesting a temperature-dependent formation mechanism.