Controlled restructuring of bidisperse silica nanospheres for size-selective nanowire growth

Abstract

We investigate neck mediated restructuring of silica nanospheres (SNs) of different radii assembled in a single-layer via sintering, resulting in the fabrication of size-tunable templates. We explore the influence of physical dimensions and mixing ratios of the participating SNs, over the neck formation and the assembly. We elucidate variation in the neck parameters pertinent to the template dimensions at every stage of sintering by a generalized geometrical model. The resultant geometry, morphological properties, and sintering parameters of SNs thin films, parametrized by particle radii, sintering duration, and mixing volume ratios, are quantified. The sintering mechanism between SNs, which are chemically and geometrically identical but of different radii, scales in accordance with Herring's law and provides valuable insights into the dominant mass transport mechanism contributing to neck formation. Control over sintering parameters facilitates the fabrication of tunable templates to grow size-selective nanowires with water-splitting, optoelectronics, and anti-reflective coating applications.