Abstract: In the early 1980s, and for more than a decade, the formation of metal/semiconductor interfaces was a central issue in semiconductor physics, with the aim of solving the intriguing Schottky barrier problem.
In this context, few pioneers initiated the study of the "other side of the problem," i.e., the early stages of the growth and of the development of the electronic properties of inverse semiconductor/metal interfaces, typically, Si/polycrystalline Au. A few years ago in Marseille, we renewed this approach with silver single crystal surfaces as substrates, using in synergy Scanning Tunneling Microscopy and Spectroscopy as well as
High-Resolution Synchrotron Radiation Photoelectron Spectroscopy. We discovered a cornucopia of exotic phenomena at Ge/Ag(111), Ge/Ag(100) and Ge/Ag(110) interfaces, as well as at Si/Ag(100) and Si/Ag(110) ones.
Specifically, weird, one-dimensional, massively parallel quantized nano-ribbons were observed at the Si/Ag(110) interface and further characterized in great details by HR-SR-PES. Density Functional Theory calculations confirmed that these silicon nano-ribbons are actually graphene-like silicon stripes, i.e., a one-atom thick novel form of silicon in a honeycomb arrangement. The discovery of silicene could possibly boost silicon further on the electronics roadmap, since, as for graphene, the silicene charge carriers are predicted to be massless relastivistic Dirac fermions.

Host: Alan S. Wan