Formation of quasi-free-standing graphene on SiC(0001) through intercalation of erbium

Activation of the carbon buffer layer on 4H- and 6H-SiC substrates using elements with high magnetic moments may lead to novel graphene/SiC-based spintronic devices. In this work, we use a variety of surface analysis techniques to explore the intercalation of Er underneath the buffer layer showing evidence for the associated formation of quasi-free-standing graphene (QFSG). A combined analysis of low energy electron diffraction (LEED), atomic force microscopy (AFM), X-ray and ultraviolet photoemission spectroscopy (XPS and UPS), and metastable de-excitation spectroscopy (MDS) data reveals that annealing at temperatures up to 1073 K leads to deposited Er clustering at the surface. The data suggest that intercalation of Er occurs at 1273 K leading to the breaking of back-bonds between the carbon buffer layer and the underlying SiC substrate and the formation of QFSG. Further annealing at 1473 K does not lead to the desorption of Er atoms but does result in further graphitization of the surface.

Automated summary

Activation of the carbon buffer layer on SiC substrates using elements with high magnetic moments may lead to novel spintronic devices. Intercalation of Er underneath the buffer layer at high temperatures results in the formation of quasi-free-standing graphene, indicating potential applications in spintronics. Further annealing leads to surface graphitization without desorption of Er atoms.