Insights into few-layer epitaxial graphene growth on4H-SiC(0001¯)substrates from STM studies

Abstract

Epitaxial carbon was grown by heating $(000\overline{1})$ silicon carbide (SiC) to high temperatures $(1450--1600\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C})$ in vacuum. A continuous graphene surface layer was formed at temperatures above $1475\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C}$. X-ray photoelectron 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, moir\'e 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.