Micromachined gas sensors based on tungsten oxide nanoneedles directly integrated via aerosol assisted CVD

Stoycheva, Toni; Annanouch, Fatima Ezahra; Gràcia, I.; Llobet, Eduard; Blackman, Christopher S.; Correig, X.; Vallejos, Stella

doi:10.1016/j.snb.2014.03.040

Cited by 54 publications

(37 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This was related to the higher surface-to-volume ratio of NS compared to NPs, although this study also highlights the need to use highly networked nanowires as opposed to (quasi) aligned nanowires for optimum gas sensing performance, as these behave similarly to single nanowire or parallel nanowire arrays [17]. Similar observations were also reported for gas microsensors based on tungsten oxide nanoparticles and nanowires grown via AACVD (Figure 3) [32]. CVD has also been demonstrated to simplify sensor processing by providing direct integration of tungsten oxide sensor materials with the sensor platform.…”

Section: Tungsten Oxidesupporting

confidence: 75%

“…CVD has also been demonstrated to simplify sensor processing by providing direct integration of tungsten oxide sensor materials with the sensor platform. This has been demonstrated particularly for aerosol assisted CVD, which has shown the selective deposition of networked or quasi-aligned tungsten oxide NS on ceramic- [33], silicon- [32] and polymer-based platforms [28].…”

Section: Tungsten Oxidementioning

confidence: 99%

See 1 more Smart Citation

Chemical Vapour Deposition of Gas Sensitive Metal Oxides

et al. 2016

View full text Add to dashboard Cite

This article presents a review of recent research efforts and developments for the fabrication of metal-oxide gas sensors using chemical vapour deposition (CVD), presenting its potential advantages as a materials synthesis technique for gas sensors along with a discussion of their sensing performance. Thin films typically have poorer gas sensing performance compared to traditional screen printed equivalents, attributed to reduced porosity, but the ability to integrate materials directly with the sensor platform provides important process benefits compared to competing synthetic techniques. We conclude that these advantages are likely to drive increased interest in the use of CVD for gas sensor materials over the next decade, whilst the ability to manipulate deposition conditions to alter microstructure can help mitigate the potentially reduced performance in thin films, hence the current prospects for use of CVD in this field look excellent.

show abstract

Section: Tungsten Oxidesupporting

confidence: 75%

Section: Tungsten Oxidementioning

confidence: 99%

Chemical Vapour Deposition of Gas Sensitive Metal Oxides

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Contrarily to WO x nanostructures with no directional orientation of its morphological units, like disordered 1D nanowires or nanorods grown by vapor‐ and liquid‐phase methods, oriented 1D WO x nanostructures, self‐organized and upright‐standing on a conducting substrate, without mutually intersecting with each other are expected to bring more advantages for practical applications in nanoscale electrochromic, field‐emission, gas‐sensing, and photonic devices. Moreover, substrate‐supported 1D nanostructures assembled in an array would enable the use of their integral properties, especially electrical, optical, or mechanical in contrast with the formation and application of single nanowires relying on their individual characteristics .…”

Section: Introductionmentioning

confidence: 99%

Exploring Electron Transport and Memristive Switching in Nanoscale Au/WO_x/W Multijunctions Based on Anodically Oxidized Al/W Metal Layers

Bendová

Hubálek

Mozalev

2016

Adv Materials Inter

View full text Add to dashboard Cite

size effect. [1][2][3] Eventual functionalization of WO x nanostructures through modifying the surface and interfacial properties by combining, doping, or decorating the pure oxide with other nanomaterials creates additional metal/semiconductor or semiconductor/semiconductor interfaces and grain boundaries capable of further infl uencing the sensing, electrical, optical, and opto-electronic properties or even introducing novel unique functionalities. [4][5][6] Contrarily to WO x nanostructures with no directional orientation of its morphological units, like disordered 1D nanowires or nanorods grown by vapor-and liquid-phase methods, [ 1,7 ] oriented 1D WO x nanostructures, self-organized and upright-standing on a conducting substrate, without mutually intersecting with each other are expected to bring more advantages for practical applications in nanoscale electrochromic, [ 8,9 ] fi eldemission, [ 10 ] gas-sensing, [ 11 ] and photonic devices. Moreover, substrate-supported 1D nanostructures assembled in an array would enable the use of their integral properties, especially electrical, optical, or mechanical in contrast with the formation and application of single nanowires relying on their individual characteristics. [ 12,13 ] Synthesis of WO x nanostructures regularly aligned on substrates has been an active and competitive area of nanoscience and nanotechnology as the arrays of 1D structures often suffer from mechanical weakness and randomly dispersed physical contacts between neighboring units, limiting their performance in a device. Besides, creating welldefi ned nanoscale metal/semiconductor electrical and thermal interfaces and boundaries by contacting the tops of 1D nanostructures assembled in an array in a reliable and reproducible manner to benefi t from the characteristics measured along the nanostructures and across relevant interfaces has been a challenge. [8][9][10][11][14][15][16][17] Surface engineering of aluminum [ 18 ] and porous anodic alumina (PAA) fi lms grown by anodic oxidation (anodizing) of aluminum have been of increasing interest for lithography-free templating of metals, dielectrics, and semiconductors. [19][20][21][22] PAA-assisted anodization [ 23 ] of certain valve metals sputtered on substrates, including tungsten, [24][25][26] has proven its potential as a reproducible method for electrochemically forming self-organized vertically aligned spatially separated 1D nanostructures (nanocolumns, rods, or tubes), being nearly ideally electrically and mechanically bonded at their bottoms either to the substrate metal [ 26 ] or to a continuous solid layer of similar metal oxide that grows at the columns/substrate-metal interface. [ 24,25 ] On the way An array of semiconducting tungsten-oxide (WO x ) nanorods, 100 nm wide and 700 nm long, is synthesized via the porous-anodic-alumina-assisted anodization of tungsten on a substrate and is modifi ed by annealing in air and vacuum. The rods buried in the alumina nanopores are self-anchored to the tungsten layer while their tops are interconnec...

show abstract

“…The sensors based on WO 3 nanocrystals are highly sensitive to reducing gases (e.g., H 2 S and H 2 ) and oxidizing gases (e.g., NO and NO 2 ). [28][29][30] Two-dimensional WO 3 nanocrystals are particularly suitable for gas-sensing applications. 31,32 Kida et al 16 introduced SnO 2 nanoparticles into WO 3 lamella-based lms by mixing two suspensions containing WO 3 $nH 2 O and SnO 2 nanoparticles, and the effective insertion of nanoparticles into WO 3 lamella stacks improved the porosity and sensitivity.…”

Section: Introductionmentioning

confidence: 99%

Microwave-assisted growth of In₂O₃ nanoparticles on WO₃ nanoplates to improve H₂S-sensing performance

et al. 2014

View full text Add to dashboard Cite

Hierarchical In 2 O 3 @WO 3 nanocomposites, consisting of discrete In 2 O 3 nanoparticles (NPs) on singlecrystal WO 3 nanoplates, were synthesized via a novel microwave-assisted growth of In 2 O 3 NPs on the surfaces of WO 3 nanoplates that were derived through an intercalation and topochemical-conversion route. The techniques of XRD, SEM, TEM and XPS were used to characterize the samples obtained. The gas-sensing properties of In 2 O 3 @WO 3 nanocomposites, together with WO 3 nanoplates and In 2 O 3 nanoparticles, were comparatively investigated using inorganic gases and organic vapors as the target substances, with an emphasis on H 2 S-sensing performance under low concentrations (0.5-10 ppm) at 100-250 C. The results show that the In 2 O 3 NPs with a size range of 12-20 nm are uniformly anchored on the surfaces of the WO 3 nanoplates. The amounts of the In 2 O 3 NPs can be controlled by changing the In 3+ concentrations in their growth precursors. The In 2 O 3 @WO 3 (In/W ¼ 0.8) sample has highest H 2 S-sensing performance operating at 150 C; its response to 10 ppm H 2 S is as high as 143, 4 times higher than that of WO 3 nanoplates and 13 times that of In 2 O 3 nanocrystals. However, the responses of the In 2 O 3 @WO 3 sensors are less than 13 upon exposure to 100 ppm of CO, SO 2 , H 2 , CH 4 and organic vapors, operating at 100-150 C. The improvement in response and selectivity of the In 2 O 3 @WO 3 sensors upon exposure to H 2 S molecules can be attributed to the synergistic effect of In 2 O 3 NPs and WO 3 nanoplates, hierarchical microstructures and multifunctional interfaces.

show abstract

Micromachined gas sensors based on tungsten oxide nanoneedles directly integrated via aerosol assisted CVD

Cited by 54 publications

References 33 publications

Chemical Vapour Deposition of Gas Sensitive Metal Oxides

Chemical Vapour Deposition of Gas Sensitive Metal Oxides

Exploring Electron Transport and Memristive Switching in Nanoscale Au/WO_x/W Multijunctions Based on Anodically Oxidized Al/W Metal Layers

Microwave-assisted growth of In₂O₃ nanoparticles on WO₃ nanoplates to improve H₂S-sensing performance

Contact Info

Product

Resources

About

Micromachined gas sensors based on tungsten oxide nanoneedles directly integrated via aerosol assisted CVD

Cited by 54 publications

References 33 publications

Chemical Vapour Deposition of Gas Sensitive Metal Oxides

Chemical Vapour Deposition of Gas Sensitive Metal Oxides

Exploring Electron Transport and Memristive Switching in Nanoscale Au/WOx/W Multijunctions Based on Anodically Oxidized Al/W Metal Layers

Microwave-assisted growth of In2O3 nanoparticles on WO3 nanoplates to improve H2S-sensing performance

Contact Info

Product

Resources

About

Exploring Electron Transport and Memristive Switching in Nanoscale Au/WO_x/W Multijunctions Based on Anodically Oxidized Al/W Metal Layers

Microwave-assisted growth of In₂O₃ nanoparticles on WO₃ nanoplates to improve H₂S-sensing performance