2 research outputs found
Nanowire-on-Nanowire: All-Nanowire Electronics by On-Demand Selective Integration of Hierarchical Heterogeneous Nanowires
Exploration
of the electronics solely composed of bottom-up synthesized
nanowires has been largely limited due to the complex multistep integration
of diverse nanowires. We report a single-step, selective, direct,
and on-demand laser synthesis of a hierarchical heterogeneous nanowire-on-nanowire
structure (secondary nanowire on the primary backbone nanowire) without
using any conventional photolithography or vacuum deposition. The
highly confined temperature rise by laser irradiation on the primary
backbone metallic nanowire generates a highly localized nanoscale
temperature field and photothermal reaction to selectively grow secondary
branch nanowires along the backbone nanowire. As a proof-of-concept
for an all-nanowire electronics demonstration, an all-nanowire UV
sensor was successfully fabricated without using conventional fabrication
processes
Laser-Induced Reductive Sintering of Nickel Oxide Nanoparticles under Ambient Conditions
This
work is concerned with the kinetics of laser-induced reductive
sintering of nonstoichiometric crystalline nickel oxide (NiO) nanoparticles
(NPs) under ambient conditions. The mechanism of photophysical reductive
sintering upon irradiation using a 514.5 nm continuous-wave (CW) laser
on NiO NP thin films has been studied through modulating the laser
power density and illumination time. Protons produced due to high-temperature
decomposition of the solvent present in the NiO NP ink, oxygen vacancies
in the NiO NPs, and electronic excitation in the NiO NPs by laser
irradiation all affect the early stage of the reductive sintering
process. Once NiO NPs are reduced by laser irradiation to Ni, they
begin to coalesce, forming a conducting material. <i>In situ</i> optical and electrical measurements during the reductive sintering
process take advantage of the distinct differences between the oxide
and the metallic phases to monitor the transient evolution of the
process. We observe four regimes: oxidation, reduction, sintering,
and reoxidation. A characteristic time scale is assigned to each regime