2 Ultrafast Laser Enabling Versatile Fabrication of Surface …
87
Fig. 2.10 Statistics of the particle size and surface porosity of the micro-nano dual-scale particle
structures. Reproduced from [55] with permission from Elsevier
2.3.3 Construction of Metal Surface
Macro-micronano-Nanowire Multiscale Structures
As one of the most promising materials for energy conversion and storage, the
direct synthesis of oxide nanowires on conductive substrates and their assembly into
three-dimensional (3D) self-supporting architectures are of great importance for the
improvement of their functions. We have proposed and experimentally demonstrated
a top-down and bottom-up combined fabrication strategy, which has the outstanding
advantages for preparing 3D self-supporting macro-micronano-nanowire multiscale
architectures directly on metal substrates in a well-controlled fashion.
As shown in the schematics in Fig. 2.12a, such a combined approach starts
from the ultrafast laser structuring of metal surfaces (Procedure 1). Through this
procedure, versatile surface micro-nano structures can be directly generated on bulk
metals (Structure 1). After that, the bulk metal samples with the micro-nano structures premade by ultrafast laser are heated in a horizontal-tube furnace for thermal
oxidation (Procedure 2). Within this process, the premade micro-nano structures
play the role of precursor, which defines the microscopic environment where the
metal-oxide nanowires are synthesized. All the structural elements involved in such
a combined approach, from the bulk metal substrate, to the ultrafast laser fabricated micro-nanoscale features, and to the oxide nanowires, together construct a
macro-micronano-nanowire multiscale architecture (Structure 2).
As a demonstration, Fig. 2.12b–e shows the nanowires grown in situ on the
ultrafast laser made one dimensional (1D) periodic structures on Cu surface. The
nanowires, with lengths over 10 µm, grow perpendicularly to the sidewalls of the
micro gratings and extend to the free space. The chemical composition of the
87
Fig. 2.10 Statistics of the particle size and surface porosity of the micro-nano dual-scale particle
structures. Reproduced from [55] with permission from Elsevier
2.3.3 Construction of Metal Surface
Macro-micronano-Nanowire Multiscale Structures
As one of the most promising materials for energy conversion and storage, the
direct synthesis of oxide nanowires on conductive substrates and their assembly into
three-dimensional (3D) self-supporting architectures are of great importance for the
improvement of their functions. We have proposed and experimentally demonstrated
a top-down and bottom-up combined fabrication strategy, which has the outstanding
advantages for preparing 3D self-supporting macro-micronano-nanowire multiscale
architectures directly on metal substrates in a well-controlled fashion.
As shown in the schematics in Fig. 2.12a, such a combined approach starts
from the ultrafast laser structuring of metal surfaces (Procedure 1). Through this
procedure, versatile surface micro-nano structures can be directly generated on bulk
metals (Structure 1). After that, the bulk metal samples with the micro-nano structures premade by ultrafast laser are heated in a horizontal-tube furnace for thermal
oxidation (Procedure 2). Within this process, the premade micro-nano structures
play the role of precursor, which defines the microscopic environment where the
metal-oxide nanowires are synthesized. All the structural elements involved in such
a combined approach, from the bulk metal substrate, to the ultrafast laser fabricated micro-nanoscale features, and to the oxide nanowires, together construct a
macro-micronano-nanowire multiscale architecture (Structure 2).
As a demonstration, Fig. 2.12b–e shows the nanowires grown in situ on the
ultrafast laser made one dimensional (1D) periodic structures on Cu surface. The
nanowires, with lengths over 10 µm, grow perpendicularly to the sidewalls of the
micro gratings and extend to the free space. The chemical composition of the