Atomic layer epitaxy (ALE) on porous substrates

Lakomaa, Eeva‐Liisa

doi:10.1016/0169-4332(94)90158-9

Cited by 109 publications

(70 citation statements)

References 15 publications

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“…Atomic layer deposition (ALD), which relies on selfterminating gas-solid reactions, is a useful method for the preparation of noble metal catalysts [1,2]. We have described the deposition of iridium from iridium(III) acetylacetonate, Ir(acac) 3 , on alumina, silica, and silicaalumina supports [3].…”

Section: Introductionmentioning

confidence: 99%

Supported iridium catalysts prepared by atomic layer deposition: effect of reduction and calcination on activity in toluene hydrogenation

Silvennoinen¹,

Jylhä²,

Lindblad

et al. 2007

Catal Lett

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Ligand removal from supported iridium catalysts prepared by atomic layer deposition from Ir(acac) 3 was studied by direct reduction in hydrogen flow and by calcination in oxygen flow followed by reduction in hydrogen flow, as well as by thermogravimetric analysis. Thermal decomposition of acac ligand residuals required high temperatures, and in samples containing no iridium the removal of carbonaceous species was not complete. Metallic iridium particles less than 2 nm in size were formed during direct reduction and larger particles upon calcination followed by reduction. The activity of the catalysts in toluene hydrogenation in most cases depended on particle size.

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Section: Introductionmentioning

confidence: 99%

Supported iridium catalysts prepared by atomic layer deposition: effect of reduction and calcination on activity in toluene hydrogenation

Silvennoinen¹,

Jylhä²,

Lindblad

et al. 2007

Catal Lett

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“…ALE process has mainly been used to grow compound thin films, such as II-VI and III-V semiconductors and oxides [2]. The self-controlled growth allows the deposition of uniform thin films not only on flat surfaces but on porous, heterogeneous surfaces, too [3]. This makes the ALE technique also an interesting method for the manufacture of catalysts.…”

mentioning

confidence: 99%

Determination of P/Al ratio in phosphorus-doped aluminium oxide thin films by XRF, RBS and FTIR

1995

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Abstract. Phosphorus-doped aluminium oxide thin films were deposited in a flow-type ALE reactor from A1C13, H20 and from either P205 or trimethylphosphate. Structural information of the films was obtained from Fourier transform infrared (FTIR) spectra. Rutherford backscattering spectroscopy (RBS) was used to quantitatively determine the composition of the films. The P/A1 intensity ratios calculated from X-ray fluorescence (XRF) results were in a linear relation with the P/A1 concentration ratios calculated from RBS results. For comparison, the intensity ratios of the phosphorus peak (P = O) at about 1250 cm-1 and the aluminium peak (A1-O) at about 950 cm-1 were determined from the IR absorption spectra. The calibration of FTIR peak intensities was done by plotting the intensity ratios of phosphorus and aluminium peaks against the P/A1 concentration ratios measured by RBS. FTIR gave also a linear calibration curve with RBS but the method is less suitable for routine analysis of P/A1 ratio than XRF.Key words: aluminium oxide, phosphorus, XRF, RBS, FTIR.In the atomic layer epitaxy (ALE) method the thin film is deposited one atomic layer at a time allowing a self-controlled growth obtained through surface saturating reactions [1]. The source materials are alternately pulsed into the reactor chamber and between the reactant doses an inert gas purge pulse is used to remove the excess of reactant and gaseous side-products. ALE process has mainly been used to grow compound thin films, such as II-VI and III-V semiconductors and oxides [2]. The self-controlled growth allows the deposition of uniform thin films not only on flat surfaces but on porous, heterogeneous surfaces, too [3]. This makes the ALE technique also an interesting method for the manufacture of catalysts.Thin films of A120 3 are extensively used for a variety of applications because of their desirable properties such as high transparency, good electrical insulating

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“…A new extension of the ALE method is its use in deposition on porous, high-surface-area substrates (silica, alumina) used as catalyst supports [43]. The basic work in this field includes the deposition of different transition metal oxides.…”

Section: Ale Activitiesmentioning

confidence: 99%