Epitaxial growth of massively parallel germanium nanoribbons by segregation through Ag(1 1 0) thin films on Ge(1 1 0)

Abstract

We investigate the epitaxial growth of low-dimensional nanostructures formed by surface segregation of germanium on single crystalline Ag(110) thin films supported by a Ge(110) template. Detailed studies of the atomic geometries have been carried out using scanning tunneling microscopy, low-energy electron diffraction, Auger electron spectroscopy, and high-resolution synchrotron radiation core-level spectroscopy. At very low Ge coverages the segregated Ge atoms form two kinds of commensurate and incommensurate quantum structures after annealing. With increasing Ge coverages, narrow stripes, 0.5 nm in width and with lengths ranging from 5 nm to 50 nm, are formed. With further increase of the Ge atoms’ segregation on the surface, the narrow stripes transform into massively parallel one-dimensional Ge nanostructures with specific widths. From a combined analysis, these fascinating quantum structures are proposed to be zig-zag germanene nanoribbons, potentially with very exciting electronic, spintronic, and topological properties.