Tin-Catalyzed Plasma-Assisted Growth of Silicon Nanowires

Abstract

A systematic study of tin-catalyzed vapor−liquid−solid (VLS) growth of silicon nanowires by plasma-enhanced chemical vapor deposition at temperatures ranging from 300 to 400 °C is presented. Wire structure, morphology, and growth rate are characterized as a function of process variables. The nanowires are observed to have a crystalline core with a polycrystalline shell due to simultaneous VLS axial growth and vapor−solid radial growth. Axial and radial growth rates are controllable through hydrogen dilution of the plasma which affects the concentration of silane radicals in the plasma. In addition, wire length is observed to saturate with increasing growth time. Post growth chemical analysis suggests this is due to etching and disappearance of tin seeds in the hydrogen plasma which occur in parallel with wire growth. This opens up the possibility of a unique in situ approach to fabricating metal-free nanowire arrays for device applications.

Silicon nanowire solar cells grown by PECVD

“…The following results have been obtained using Sn catalysts. While Sn is prone to oxidize and requires a reactive environment to catalyze SiNW growth, it is expected to introduce shallower energy levels in the silicon bandgap than gold [16] and has been observed to etch away the system [17]. Sn also has an unusually low eutectic point with Si and can catalyze nanowire growth at temperatures of 250°C [18].…”

Controlling the shell microstructure in a low-temperature-grown SiNWs and correlating it to the performance of the SiNWs-based micro-supercapacitor

“…2 that the nanowire has a core-shell structure. Detailed information on the core-shell structure and tapering of SiNWs can be found in the literature (Adachi et al 2013;Misra et al 2013;Rathi et al 2011). It is clear from Fig.…”

Synthesis of Si-NWs by PECVD using Sn as catalyst on TCO thin film for optoelectronic devicies

“…Density reduction phenomenon occurs due to corrosion of Sn in H 2 environment through a stimulating effect of plasma leading to a chemical reaction to form SnH x gaseous products. This has also been mentioned in the study of Somikumar [4]. Growth of Si-NWs following vapor liquid solid (VLS) mechanism must have three aspects, namely (i) synthesized temperature is the higher eutectic point, (ii) there are catalyst metal nanoparticles and (iii) catalyst metal nanoparticles have been observed on the head of Si-NWs after the synthesis process.…”

“…Tin-catalyzed silicon nanowires have been synthesized by Rathi [4] and Jeon [5]. But all were integrated on substrates such as silicon wafers, corning or glass.…”