Silicene and germanene: Silicon and germanium in the "flatland"

Atomically thin two dimensional (2D) materials offer ultimate thickness scaling of nanoelectronic devices which could substantially improve the electrostatic control and enable a number of low power versatile applications. Silicene and germanene, the silicon and germanium equivalents of graphene have attracted an immense interest. The progress in the growth and physical characterization of these materials will be reviewed. Emphasis will be given on the most stable phases of silicene focusing on the electronic band-structure attempting to answer the question about the existence of Dirac Fermions. The stability and the challenges for field effect device processing are discussed and the new trends towards multilayer silicene and growth on non-metallic/insulating substrates are reviewed. (C) 2014 Elsevier B.V. All rights reserved.