Structures and energetics of hydrogen-terminated silicon nanowire surfaces

Abstract

The analysis and density-functional tight-binding simulations of possible configurations of silicon nanowires (SiNWs) enclosed by low-index surfaces reveal a number of remarkable features. For wires along <100>, <110>, and <111> directions, many low-index facet configurations and cross sections are possible, making their controlled growth difficult. The 112 wires are the most attractive for research and applications because they have only one configuration of enclosing low-index facets with a rectangular cross section, enclosed with the most stable (111) facet and the (110) facet next to it. In general, the stability of the SiNWs is determined by a balance between (1) minimization of the surface energy gamma(111)<gamma(110)<gamma(001), and (2) minimization of the surface-to-volume ratio [svr; svr(hexagonal)>svr(rectangular)>svr(triangular)]. The energy band gaps follow the order of <100>wires > <112>wires > <111>wires > <110>wires. The results are compared with our recent scanning tunneling microscopy and transmission electron microscopy data.

Atomic and electronic structures of doped silicon nanowires: A first-principles study

“…6,7 Structures and energetics of H-SiNWs were reported by using DFT tight binding method. 8 By passivating the SiNWs surface with H and some halogens including Br, Cl, and I, the electronic structure of wires with diameter ranging from 0.6 to 3 nm has been studied using ab initio DFT calculations. 9 Impurity doped SiNWs have also attracted attention since the dopant atoms provide excess carriers required in device applications, such as diodes and transistors.…”

Silicon-Based Third Generation Photovoltaics

“…These results demonstrate a clear preference for growth along the <110> direction in the smallest Si NWs and along <111> direction in larger ones (Zhong et al, 2007). Cross-sectional HRTEM analysis has revealed that the nanowires could have triangular, rectangular and hexagonal cross section with well -developed facets (Vo et al, 2006) (Jie et al, 2006) (Zhang et al, 2005). The VLS method permits to fabricate the nanowires of well-defined length with diameters as small as 3 nm (Wu et al, 2004).…”

Theoretical Study of Carbon Clusters in Silicon Carbide Nanowires

“…We examined C clusters in 3C-SiC bulk and in hydrogenpassivated SiC NWs grown along the [111] and [100] directions [7,31]. We considered SiC NWs with diameter of about 10Å, constructed from the 3C-SiC structure [5,32].…”