Silicon (Si) nanowires have garnered significant interest
for their
potential applications in Si-based thermoelectrics, primarily due
to their low thermal conductivity. While there are several methods
to obtain Si nanowires, their density has been a limiting factor,
resulting in a low power density that can be achieved by thermoelectric
generators. To address this limitation, metal-assisted chemical etching
(MACE) has been developed, enabling the creation of high-density nanopillar
“forests”. This technique overcomes the previous density
constraints. However, Si nanopillars protrude from a bulk Si wafer,
which adds its thermal and electric resistivity to those of nanopillars,
ultimately reducing the overall power density that can be attained.
In this paper, we demonstrate how precise control of pre- and post-MACE
processing allows for the creation of fully self-sustained quasi-1D
Si nanostructures. We additionally demonstrate that pre-MACE Si processing
does not control nanopillar bundling; rather, it primarily determines
their shape. This outcome is attributed to the formation of gas nanobubbles
during the initial steps of MACE.