Silicon nanowire growth on poly‐silicon‐on‐quartz substrates formed by aluminum‐induced crystallization

Abstract

The vertical growth of Si nanowires on non‐monocrystalline substrates is of significant interest for photovoltaics and other energy harvesting applications. In this paper, we present results on using poly‐Si layers formed by aluminum‐induced crystallization (AIC) on fused quartz wafers as an alternative substrate for the vapor‐liquid‐solid (VLS) growth of vertical Si nanowires. Oxidation of the Al surface to Al2O3 before the a‐Si deposition was shown to be a key requirement in the formation of the poly‐Si template since it promotes the crystallization of the a‐Si into Si(111) which is required for vertical silicon nanowire growth. The effect of Al deposition technique (DC sputtering versus thermal evaporation) on a‐Si crystallization and Si nanowire growth was investigated. The use of Al thermal evaporation yielded AIC poly‐Si layers with the highest fraction of 〈111〉 grains as measured by orientation imaging microscopy (OIM) which enabled the growth of vertical Si nanowires. Cross‐sectional transmission electron microscopy analysis confirmed that the 〈111〉 Si nanowires grew epitaxially off of {111}poly‐Si grains in the AIC layer. This study demonstrates the potential of using AIC poly‐Si as a template layer for the vertical growth of silicon nanowires on amorphous substrates.

Metal-induced layer exchange of group IV materials

“…In fact, different materials such as GaAs [188,207], BaSi 2 [208,209], ZnO [150] and GaN [210] were developed on glass using the LE buffer layer. Additionally, aligned nanowires were synthesized on glass [123,[211][212][213] and even on a flexible plastic substrate [214] using the property that the nanowires grow in a specific orientation (figures 15(b) and (c)). The LE layer is also useful for seeding rapid-melting growth of Ge [215].…”

Effects of Al grain size on metal-induced layer exchange growth of amorphous Ge thin film on glass substrate

“…In MILE, the lower growth rate leads to the higher (111) fraction [19,40,47,48]. On the other hand, the (111) fraction decreases with increasing the surface roughness of Al [46,48]. The sample with TAl = 100 o C presented the highest (111) fraction among the samples in this study likely owing to the good balance between the growth rate and the surface roughness of Al.…”

“…The layer exchange phenomenon was originally found in the reaction between Al and Si [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. The mechanism has been investigated over a decade from the perspective of both technological and scientific points, which is summarized as follows.…”

Crystallization of Si Templates of Controlled Shape, Size, and Orientation: Toward Micro- and Nanosubstrates

“…They can be precisely localized and their shape can be controlled. Their [111] orientation is well suited to semiconductor epitaxial growth, and their size can be tuned to obtain epitaxial nano- or microstructures, such as nanowires ,, or larger pads of semiconductor with the idea that a single device could be fabricated on one pad. In this latter case, pads of a few μm 2 would be suitable.…”