Layer-by-layer nanotransfer printing of a 3D catalyst for MacEtch-fabricated ordered arrays of Si nanopillars and nanowires with a designed tilt and cross-section shape

This work further develops the method of nanotransfer printing of large-area nanoscaled Au patterns for the metal-assisted catalytic etching (MacEtch) of a Si substrate and the formation of nanopillar or nanowire arrays. A technology for the sequential nanotransfer printing of 1D Au gratings was developed, thus, enabling the creation of multilayer 3D Au catalyst meshes with nanowindows for MacEtch, which are impossible to create using other known nanolithographic methods. The catalytic etching of silicon using these 3D Au catalysts significantly differs from the well-studied etching processes using flat Au patterns. As a result, ordered arrays of Si nanowires with a specified tilt and cross section, as well as superperiodic arrays of Si nanopillars, were fabricated. The studies conducted in this work confirm that the catalyst movement during catalytic etching is determined by van der Waals forces, which significantly influence the tilt and cross-section of the formed nanowires. The work demonstrates the control of multilayer 3D Au catalyst movement during MacEtch using both its geometry and the etchant composition.