One‐Step Fabrication of Nanocrystalline Nanonetwork SnO₂ Gas Sensors by Integrated Multilaser Processing

Abstract

An integrated multilaser process is developed to fabricate nanocrystalline nanonetwork SnO2 gas sensors in one integrated procedure, which combines electrodes fabrication, nanomaterials deposition, and postannealing. Interdigit electrodes are fabricated on an Au‐coated fused silica substrate using a picosecond (ps) laser, which ablates the Au coating from the back of the substrate to pattern the electrodes. A novel transmitted Ps laser deposition (TPLD) process is designed to deposit SnO2 nanonetwork on the interdigit electrodes with precise deposition area control under a close target‐to‐substrate distance. The obtained SnO2 nanonetwork is in situ postannealed by a CO2 laser to improve the crystallinity, while the nano morphology and grain size keep intact. To investigate the morphology and formation process of the nanonetwork, the microstructure of the laser‐deposited SnO2 layer is characterized. The crystallization control of CO2 laser annealing is investigated through analyzing the Raman spectrum, X‐ray diffraction (XRD) patterns, and lattice structures of the samples. By exposed to H2 atmosphere, the fabricated gas sensor is demonstrated for H2 monitoring.

Polymerization-Induced Aggregation Approach toward Uniform Pd Nanoparticle-Decorated Mesoporous SiO2/WO3 Microspheres for Hydrogen Sensing

“…The working principle of SMOs gas sensors is based on their chemiresistance features, that is, the resistance of SMOs can change rapidly upon contact with guest molecules followed by gas adsorption and catalytic reaction. − In the last decade, various SMOs such as ZnO, − SnO 2 , − MoO 3 , − In 2 O 3 , − and WO 3 , have been extensively explored as sensitive materials for gas sensors toward hydrogen. Among various SMOs, WO 3 -based composites have been considered an ideal sensing material with great potential for applications because they have the advantages of a wide band gap (2.6–3.0 eV), , tunable redox property, and good stability .…”

Integrated co-axial electrospinning for a single-step production of 1D aligned bimetallic carbon fibers@AuNPs–PtNPs/NiNPs–PtNPs towards H2 detection

“…Recently, people have tried to reinforce on-chip fabrication of sensor devices, but such approaches were found to involve multi stage processes, which results in practical issues, a fact which hampers their mass production. 22 Such difficulties might be surpassed by single stage development of aligned core-shell type hybrid CFs with metals/bimetals over the CFs using coaxial electrospinning process. However, there are no reports on single step fabrication of carbon nanofibers@metal/bimetal-based hybrid heterojunctions based on co-axial electrospinning with in-situ photo reduction for room temperature H2 gas sensor applications.…”