Highly Doped Si Single Crystal Nanowires via Metallic Flux Nanonucleation

Abstract

Ever since the advent of scalable production of nanodevices, the search for optimal fabrication techniques of low dimensional materials has gained the attention of scientists and engineers all over the world. In particular, the fabrication of silicon nanowires is being increasingly investigated, due to their potential integration into novel technologies such as biological and optical sensors, solar cells, power generators, and transistors, among others. In this context, this work reports the single-step fabrication of Ga-doped Si bulk and nanowire single crystals. They were obtained through the Metallic Flux Nanonucleation (MFNN) technique, where a nanoporous alumina template was employed to define the nanowire morphology, while Ga was used as flux to both lower the Si melting point and dope the crystals. Our results show that Ga-doped silicon bulk crystals were successfully fabricated via MFNN. The carrier concentration was determined by probing the Hall effect and was found to be (2.5 ± 0.2) x 1019 cm−3. Silicon nanowires were simultaneously obtained, presenting an average wire diameter of 125 ± 26 nm and length up to several tens of microns. These results open the possibility to easily fabricate heavily doped intermetallic cylindrical nanowires, with versatility both on the nanowire composition and the doping element.