Insights into few-layer epitaxial graphene growth on 4H-SiC(000(1)over-bar substrates from STM studies

Epitaxial carbon was grown by heating (000 (1) over bar) silicon carbide (SiC) to high temperatures (1450-1600 degrees C) in vacuum. A continuous graphene surface layer was formed at temperatures above 1475 degrees C. X-ray photo-electron spectroscopy (XPS) and scanning tunneling microscopy (STM) were extensively used to characterize the quality of the few-layer graphene (FLG) surface. The XPS studies were useful in confirming the graphitic composition and measuring the thickness of the FLG samples. STM studies revealed a wide variety of nanometer-scale features that include sharp carbon-rich ridges, moire superlattices, one-dimensional line defects, and grain boundaries. By imaging these features with atomic-scale resolution, considerable insight into the growth mechanisms of FLG on the carbon face of SiC is obtained.