Atomic layer growth of TiO2 on silica

Lakomaa, Eeva‐Liisa; Haukka, Suvi; Suntola, Tuomo

doi:10.1016/0169-4332(92)90506-s

Cited by 102 publications

(70 citation statements)

References 9 publications

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“…In particular, the CVD method permits good conformal coverage of the substrate surface, yielding layers with tuneable crystallinity, chemical composition, and morphology. Further interesting perspectives arise from the possibility of achieving a vapor infiltration and subsequent nucleation into porous or fibrous structures, [13,18] which has been applied to the preparation of semiconductor clusters in the ªinternal surfacesº of zeolites [19±21] and macroporous metal oxides. [22] The SG route enables the tailoring of oxo-hydroxo macromolecular networks (from gels to fully densified materials in the form of powders, composites, fibers, ¼) starting from suitable precursor solutions.…”

Section: Introductionmentioning

confidence: 99%

Innovative Approaches to Oxide Nanosystems: CeO₂‐ZrO₂ Nanocomposites by a Combined PE‐CVD/Sol–Gel Route

Armelao¹,

Barreca

Bottaro

et al. 2004

Chemical Vapor Deposition

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A novel combined PE-CVD/sol±gel approach to oxide-based nanosystems is proposed and employed for the synthesis of CeO 2 ±ZrO 2 nanocomposites. The method consists of the plasma-enhanced (PE) CVD of ceria (guest) on a zirconia xerogel ZrO x (OH) y (OR) z (host) prepared by sol±gel (SG) at a temperature of 200 C. The system evolution under annealing in air (600 C and 900 C, 1 h) and its mutual relationships with the synthesis conditions were investigated in detail by a multi-technique characterization. The proposed synthetic pathway enables the synthesis of CeO 2 ±ZrO 2 nanostructured systems ranging from composites to solid solutions, as a function of thermal treatment and Ce/Zr ratio as well. In this framework, particular attention is devoted to achieving an intimate Ce/Zr intermixing by exploiting the synergy between the SG xerogel properties (porosity, ±OH content) and the peculiar actions exerted by plasma (ablation/deposition, infiltration power). Such features enable an in-depth penetration of ceria into the inner zirconia xerogel layers already in the as-grown systems.

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Section: Introductionmentioning

confidence: 99%

Innovative Approaches to Oxide Nanosystems: CeO₂‐ZrO₂ Nanocomposites by a Combined PE‐CVD/Sol–Gel Route

Armelao¹,

Barreca

Bottaro

et al. 2004

Chemical Vapor Deposition

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“…Although ALD of TiO 2 from TiCl 4 and water has been intensively investigated since the invention of the ALD method, [14][15][16][17][18][19][20][21][22][23][24][25][26][27] the role of HCl is not clear yet. Here we investigate the role of HCl which may be one of origins for the non-ideality in TiO 2 ALD.…”

Section: Introductionmentioning

confidence: 99%

Role of HCl in Atomic Layer Deposition of TiO₂Thin Films from Titanium Tetrachloride and Water

Leem¹,

Park²,

Li³

et al. 2014

Bulletin of the Korean Chemical Society

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Atomic layer deposition (ALD) of TiO 2 thin film from TiCl 4 and H 2 O has been intensively studied since the invention of ALD method to grow thin films via chemical adsorptions of two precursors. However the role of HCl which is a gaseous byproduct in ALD chemistry for TiO 2 growth is still intriguing in terms of the growth mechanism. In order to investigate the role of HCl in TiO 2 ALD, HCl pulse and its purging steps are inserted in a typical sequence of TiCl 4 pulse-purge-H 2 O pulse-purge. When they are inserted after the first-half reaction (chemisorption of TiCl 4 ), the grown thickness of TiO 2 becomes thinner or thicker at lower or higher growth temperatures than 300 o C, respectively. However the insertion after the second-half reaction (chemisorption of H 2 O) results in severely reduced thicknesses in all growth temperatures. By using the result, we explain the growth mechanism and the role of HCl in TiO 2 ALD.

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“…This effect is due to relatively harmless starting materials needed for synthesis of these materials. For instance, metal chlorides or iodides combined with water vapor [19][20][21][22][23][24][25][26] or oxygen [27] can be used as precursors to prepare thin oxide films. By contrast, highly toxic AsH 3 , H 2 Se, and H 2 S are often the starting materials for the synthesis of III-V and II-VI compounds used in electronic and optoelectronic devices.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, TiO 2 , a very promising material for a number of applications, can be stabilized in the amorphous phase [13,20,21,23] and at least five crystalline phases. Anatase [9, 13-15, 17, 19-21, 23-28] and rutile [19][20][21][24][25][26][27] are the crystalline phases that are usually formed at normal and low pressures. In addition, brookite has been observed in TiO 2 single crystals [31], powders [31], and thin films [32] at normal conditions.…”

Section: Introductionmentioning

confidence: 99%

Structural study of TiO2 thin films by micro-Raman spectroscopy

et al. 2006

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Abstract:The Raman spectroscopy method was used for structural characterization of TiO 2 thin films prepared by atomic layer deposition (ALD) and pulsed laser deposition (PLD) on fused silica and single-crystal silicon and sapphire substrates. Using ALD, anatase thin films were grown on silica and silicon substrates at temperatures 125-425 • C. At higher deposition temperatures, mixed anatase and rutile phases grew on these substrates. Post-growth annealing resulted in anatase-to-rutile phase transitions at 750 • C in the case of pure anatase films. The films that contained chlorine residues and were amorphous in their as-grown stage transformed into anatase phase at 400 • C and retained this phase even after annealing at 900 • C. On single crystal sapphire substrates, phase-pure rutile films were obtained by ALD at 425 • C and higher temperatures without additional annealing. Thin films that predominantly contained brookite phase were grown by PLD on silica substrates using rutile as a starting material.

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Atomic layer growth of TiO2 on silica

Cited by 102 publications

References 9 publications

Innovative Approaches to Oxide Nanosystems: CeO₂‐ZrO₂ Nanocomposites by a Combined PE‐CVD/Sol–Gel Route

Innovative Approaches to Oxide Nanosystems: CeO₂‐ZrO₂ Nanocomposites by a Combined PE‐CVD/Sol–Gel Route

Role of HCl in Atomic Layer Deposition of TiO₂Thin Films from Titanium Tetrachloride and Water

Structural study of TiO2 thin films by micro-Raman spectroscopy

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Atomic layer growth of TiO2 on silica

Cited by 102 publications

References 9 publications

Innovative Approaches to Oxide Nanosystems: CeO2‐ZrO2 Nanocomposites by a Combined PE‐CVD/Sol–Gel Route

Innovative Approaches to Oxide Nanosystems: CeO2‐ZrO2 Nanocomposites by a Combined PE‐CVD/Sol–Gel Route

Role of HCl in Atomic Layer Deposition of TiO2Thin Films from Titanium Tetrachloride and Water

Structural study of TiO2 thin films by micro-Raman spectroscopy

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Product

Resources

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Innovative Approaches to Oxide Nanosystems: CeO₂‐ZrO₂ Nanocomposites by a Combined PE‐CVD/Sol–Gel Route

Innovative Approaches to Oxide Nanosystems: CeO₂‐ZrO₂ Nanocomposites by a Combined PE‐CVD/Sol–Gel Route

Role of HCl in Atomic Layer Deposition of TiO₂Thin Films from Titanium Tetrachloride and Water