Tungsten hexacarbonyl and hydrogen peroxide as precursors for the growth of tungsten oxide thin films on titania nanoparticles

Jackson, David H. K.; Dunn, Bryan A.; Guan, Yingxin; Kuech, T. F.

doi:10.1002/aic.14397

Cited by 9 publications

(14 citation statements)

References 36 publications

(61 reference statements)

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“…Unfortunately, more details were not provided for this ALD process. The ALD process of WO 3 using W(CO) 6 / H 2 O 2 was investigated by Jackson et al 212 In the range of 180-200 C, they found that the precursor pair of W(CO) 6 /H 2 O 2 could not achieve a pure form of ALD growth, but continuous dosing of W(CO) 6 could always increase the growth rates. They also noticed that W(CO) 6 was prone to decompose even at a temperature of 80 C, and this explained the continuous unsaturated growth of WO 3 with extended dosing of W(CO) 6 .…”

Section: Layered Transition Metal Oxides Moomentioning

confidence: 99%

Atomic Layer Deposition of Two-Dimensional Layered Materials: Processes, Growth Mechanisms, and Characteristics

Cai

Han

Wang

et al. 2020

Matter

111

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Since the discovery of graphene, there has been an ever-increasing interest in two-dimensional (2D) layered materials with exceptional properties. To this end, a variety of synthesis methods have been developed. However, it is still challenging to produce large-scale high-quality single-crystalline 2D materials. In this regard, atomic layer deposition (ALD) has recently shown great promise and has stimulated more and more research efforts, ascribed to its unique growth mechanism and distinguished capabilities to achieve nanoscale films with excellent uniformity, unrivaled conformality, and atomic-scale controllability. This review comprehensively summarizes recent progress on ALD for 2D atomic sheets, including 25 different materials and more than 80 ALD processes. This work highlights different technical routes to ALD, their precise controllability, and their underlying principles for 2D materials. It is expected that this work will help boost more research efforts for controllable growth of high-quality 2D materials via ALD.

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Section: Layered Transition Metal Oxides Moomentioning

confidence: 99%

Atomic Layer Deposition of Two-Dimensional Layered Materials: Processes, Growth Mechanisms, and Characteristics

Cai

Han

Wang

et al. 2020

Matter

111

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“…Tungsten hexacarbonyl W(CO) 6 is one of the most used precursors. [196][197][198][199][200] Using ozone as oxygen source, narrow ALD window between 195 and 205°C with a GPC of 0.2 Å/cycle is noted. 196,197 While Nandi and Sarkar 196 report amorphous films that could be converted to monoclinic WO 3 upon annealing, Malm et al 197 obtain partially crystallized as-deposited films that can considerably be improved by annealing at 600-1000°C under oxygen or nitrogen atmospheres.…”

Section: Tungsten Oxidementioning

confidence: 99%

“…On the other hand, from H 2 O 2 and W(CO) 6 , thin WO x films are successfully grown onto TiO 2 particles using a fluidized bed reactor. 198 The WO x films result from both ALD-like and CVD-based growth modes, the determined W/Ti atomic ratio being partially dependent on the tungsten and oxygen precursor pulse lengths.…”

Section: Tungsten Oxidementioning

confidence: 99%

“…These films inhibit the TiO 2 anatase-to-rutile phase conversion at high temperature annealing, without WO 3 crystallization. 198 Using H 2 O as oxygen source, the surface roughness increases and the initial amorphous layer completely crystallizes into polycrystalline film under post-annealing. 199,200 In addition to W(CO) 6 , WF 6 reacted with water is widely studied and a very low deposition rate, ascribed to poor adsorption of WF 6 on the oxide surface, is observed.…”

Section: Tungsten Oxidementioning

confidence: 99%

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Atomic layer deposition of stable 2D materials

Hao¹,

Marichy²,

Journet³

2018

2D Mater.

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Following the graphene isolation, strong interest in two dimensional (2D) materials has been driven by their outstanding properties. Their typical intrinsic structure, including strong in-plane covalent bonding and weak out-of-plane Van der Waals interaction, makes them highly promising in diverse areas such as electronics, catalysis, and environment. Growth of 2D materials requires a synthesis approach able to control the deposition onto a support at the atomic scale. Thanks to their simplicity, versatility and ability to control thickness at the angstrom level, Atomic Layer Deposition (ALD) and its variant Atomic Layer Etching (ALET) appear as ones of the most suited techniques to synthesize 2D materials. The development of ALD technique for fabricating 2D materials in the last ten years justifies reviewing its most recent groundbreaking discoveries and progresses. Particular attention will be paid to stable 2D materials especially graphene, h-BN, Mo and W dichalcogenides and few monolayered metal oxides. Specificities and outputs of ALD for 2D material as well as emerging directions and remaining technical challenges will be highlighted. layers. This kind of materials exhibits interesting properties related to their size restriction: electronic confinement, modifying both optical and electronic properties, and high surface to volume ratio that affects the mechanical and chemical properties. 4,5 Therefore, 2D materials are highly attractive due to their potential in cutting edge domains such as micro-, and opto-electronics 4,6 as well as renewable energy, 4,7-9 catalysis, 10,11 gas sensing 12,13 and environment. 4,7,14,15 They are also exciting because of their possibility to be stacked into VdW heterostructures combining and/or tuning their chemical and physical properties. 6,[16][17][18] However, since 2D materials are atomically thin, a suitable manufacturing process capable of controlling their fabrication in terms of structure, composition, thickness, defects, purity and crystallinity without degradation of their original properties is necessary. Two approaches can be considered: the top-down and bottom-up synthetic routes. 19 Historically, top-down approach has first been developed using mechanical and chemical exfoliation techniques, 1,2,20,21 the first example being the well-known graphene exfoliation using scotch tape.Later on, etching processes have been adapted. Recently, Atomic Layer Etching (ALET), 22 the top down variant of Atomic Layer Deposition (ALD), has been introduced for fabricating 2D materials. On the other hand, bottom-up techniques have largely been developed using conventional thin film deposition. These techniques include sputtering, evaporation and Chemical Vapor Deposition (CVD). 3,23,24 However, they are mainly based on either high temperature processes, substrate restrictive deposition or low thickness control. 21,25,26 Amongst all the fabrication processes, ALD appears to be one of the most suited techniques to synthesize 2D materials, because of its simplicity, versatility and c...

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“…However, this claim is somewhat controversial because it is generally accepted that a full Al2O3 monolayer (0.38 nm) can only be obtained after 3-4 ALD cycles (George, 2010). Similarly, for a material with a low growth-per-cycle (GPC), WOx, a film of 0.46 nm was measured by TEM after 25 cycles of W(CO)6 and H2O2 on commercial Degussa P25 TiO2 nanoparticles (Jackson, Dunn, Guan, & Kuech, 2014). To our knowledge, the thickest ALD film grown on a powder support is a ~110 nm Al2O3 passivation barrier deposited onto Fe powder particles (Moghtaderi, Shames, & Doroodchi, 2006).…”

Section: Ald Nanostructuringmentioning

confidence: 99%

Advances in scalable gas-phase manufacturing and processing of nanostructured solids: A review

et al. 2017

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Although the gas-phase production of nanostructured solids has already been carried out in industry for decades, only in recent years has research interest in this topic begun to increase. Nevertheless, despite the remarkable scientific progress made recently, many long-established processes are still used in industry.Scientific advancements can potentially lead to the improvement of existing industrial processes, but also to the development of completely new routes. This paper aims to review state-of-the-art synthesis and processing technologies, as well as the recent developments academic research. Flame reactors that produce inorganic nanoparticles on industrial-and lab-scales are described, alongside a detailed overview of the different systems used for the production of carbon nanotubes and graphene. We discuss the problems of agglomeration and mixing of nanoparticles, which are strongly related to synthesis and processing. Finally, we focus on two promising processing techniques, namely nanoparticle fluidization and atomic layer deposition.

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Tungsten hexacarbonyl and hydrogen peroxide as precursors for the growth of tungsten oxide thin films on titania nanoparticles

Cited by 9 publications

References 36 publications

Atomic Layer Deposition of Two-Dimensional Layered Materials: Processes, Growth Mechanisms, and Characteristics

Atomic Layer Deposition of Two-Dimensional Layered Materials: Processes, Growth Mechanisms, and Characteristics

Atomic layer deposition of stable 2D materials

Advances in scalable gas-phase manufacturing and processing of nanostructured solids: A review

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