Abstract

The variety of existing carbon allotropes has put this element into the focus of basic as well as applied research for a long time. Its three-dimensional crystallographic forms—graphite and diamond—are known from the ancient times and widely used in industrial applications. Starting in the 1980s, lower dimensional forms of carbon have been discovered, namely, the zero-dimensional fullerenes or cage molecules (Kroto et al. 1985) and the one-dimensional carbon nanotubes (CNTs) (Iijima 1991), which are now extensively studied due to their remarkable mechanical and electronic properties. At the same time, despite very intensive research in the area, no two-dimensional form of carbon has been known until very recently.