Silicon Nanowires: A Review on Aspects of their Growth and their Electrical Properties

Abstract

This paper summarizes some of the essential aspects of silicon‐nanowire growth and of their electrical properties. In the first part, a brief description of the different growth techniques is given, though the general focus of this work is on chemical vapor deposition of silicon nanowires. The advantages and disadvantages of the different catalyst materials for silicon‐wire growth are discussed at length. Thereafter, in the second part, three thermodynamic aspects of silicon‐wire growth via the vapor–liquid–solid mechanism are presented and discussed. These are the expansion of the base of epitaxially grown Si wires, a stability criterion regarding the surface tension of the catalyst droplet, and the consequences of the Gibbs–Thomson effect for the silicon wire growth velocity. The third part is dedicated to the electrical properties of silicon nanowires. First, different silicon nanowire doping techniques are discussed. Attention is then focused on the diameter dependence of dopant ionization and the influence of interface trap states on the charge carrier density in silicon nanowires. It is concluded by a section on charge carrier mobility and mobility measurements.

Preparation and characterization of silicon nanowires catalyzed by aluminum

“…However, SiNWs were also grown via the VLS mechanism by Schmidt et al [22] using an Al catalyst at temperatures between 580°C and 700°C. The VSS growth mechanism has been reported for the growth of SiNWs using other catalysts such as Ti [25].…”

“…The eutectic point of the Al-Si system at 577 °C was at a low Si concentration of 12.6% [22,23], as shown in the Al-Si phase diagram in Fig. 6.…”

Fabrication and optical simulation of vertically aligned silicon nanowires

“…First, the sample was annealed at 700°C to produce Au nanoparticles. The resulting surface was exposed to SiH 4 gas for 30 min at 1.1 mbar (flow of H 2 /SiH 4 , QH 2 /SiH 4 = 150/ 12 sccm) and heated at high temperatures (400-550°C) to produce a dense array of nanowires (Schmidt et al 2009;Suzuki et al 2007;Wagner and Ellis 1964). A schematic diagram of the process is shown in Fig.…”

Nanostructuring methods for enhancing light absorption rate of Si-based photovoltaic devices: A review

“…[21][22][23][24][25] VLS has been introduced and developed to combine with high techniques: annealing in reactive atmosphere, laser ablation and evaporation. [26][27][28][29][30][31][32] These techniques can generate nanoscale catalytic droplets with precise size control, high yielding rate, and purity.…”