Monolithic growth of ultrathin Ge nanowires on Si(001) Journal Article

Author(s): Zhang, Jianjun; Katsaros, Georgios; Montalenti, Francesco; Scopece, Daniele; Rezaev, Roman O; Mickel, Christine H; Rellinghaus, Bernd; Miglio, Leo P; De Franceschi, Silvano; Rastelli, Armando; Schmidt, Oliver G
Article Title: Monolithic growth of ultrathin Ge nanowires on Si(001)
Abstract: Self-assembled Ge wires with a height of only 3 unit cells and a length of up to 2 micrometers were grown on Si(001) by means of a catalyst-free method based on molecular beam epitaxy. The wires grow horizontally along either the [100] or the [010] direction. On atomically flat surfaces, they exhibit a highly uniform, triangular cross section. A simple thermodynamic model accounts for the existence of a preferential base width for longitudinal expansion, in quantitative agreement with the experimental findings. Despite the absence of intentional doping, the first transistor-type devices made from single wires show low-resistive electrical contacts and single-hole transport at sub-Kelvin temperatures. In view of their exceptionally small and self-defined cross section, these Ge wires hold promise for the realization of hole systems with exotic properties and provide a new development route for silicon-based nanoelectronics.
Keywords: Silicon; Cross section; Quantitative agreement; Nanowires; Atomically flat surface; Catalyst-free method; Electrical contacts; Exotic properties; Hole systems; Longitudinal expansions; Self-assembled; Si(0 0 1); Silicon-based; Single wires; Thermodynamic model; Triangular cross-sections; Ultra-thin; Unit cells; Germanium; Molecular beam epitaxy
Journal Title: Physical Review Letters
Volume: 109
Issue 8
ISSN: 1079-7114
Publisher: American Physical Society  
Date Published: 2012-08-23
Start Page: Article number 085502
DOI: 10.1103/PhysRevLett.109.085502
Notes: We acknowledge the financial support by the DFG SPP1386, P. Chen and D. J. Thurmer for MBE assistance, R. Wacquez for providing the ultrathin SOI wafers, and G. Bauer, Y. Hu, X. Jehl, S. Kiravittaya, C. Klöffel, E. J. H. Lee, F. Liu, D. Loss, and S. Mahapatra for helpful discussions. G. K. acknowledges support from the European commission via a Marie Curie Carrer Integration Grant. S. D. F. acknowledges support from the European Research Council through the starting grant program
Open access: yes (repository)