Distinct termination morphologies for vertically aligned carbon nanotube forests Vinten, P.; Marshall, P.; Lefebvre, J.; Finnie, P.Contact us / Contactez nous: nparc.cisti@nrc-cnrc.gc.ca. Abstract Vertically aligned carbon nanotube forests, including single-walled nanotubes, are imaged optically as they grow in situ from cobalt/alumina catalyst using water-assisted acetylene chemical vapor deposition. Three distinct termination morphologies are identified and investigated optically and via scanning electron microscopy. Quantitative growth dynamics are extracted and show gradual deceleration and sudden termination of growth. The termination morphology is discussed in terms of the balance of forces within the forest. We speculate that sudden termination is a collective effect arising from an imbalance in these forces.

4 ]. Varying levels of residual carbon and nitrogen were detected in the films grown from each precursor. Analysis by X-ray diffraction (XRD) indicates that films grown from both precursors exist predominantly in the thermodynamically stable monoclinic phase. Scanning electron microscopy (SEM) shows that the morphology of the HfO 2 films from each precursor is markedly different, with films deposited from [Hf(NMe 2 ) 4 ] having a well-defined columnar crystalline structure, whereas films grown from [Hf(ONEt 2 ) 4 ] are smoother with little evidence of columnar structure. Full crystal structure data for [Hf(NMe 2 ) 4 ] are given, and the dielectric properties of [Al/HfO 2 /n-Si(100)] MOS capacitors, fabricated using each precursor, are also reported.

Thin films of praseodymium oxide have been deposited by liquid injection MOCVD using the volatile praseodymium alkoxide, [Pr(mmp) 3 ] (mmp = 1-methoxy-2-methyl-2-propanolate, OCMe 2 CH 2 OMe). The films were grown over a wide range of substrate temperatures (250±600 C) and were found to consist predominantly of the Pr 6 O 11 phase. Praseodymium silicate films containing~16±22 at.-% Si were deposited over the temperature range 350±550 C using [Pr{N(SiMe 3 ) 2 } 3 ] in the absence of any additional Si source.

Silver nanoparticles are being developed for applications in plasmonics, catalysts and analytical methods, amongst others. Herein, we demonstrate the growth of silver nanoparticles using an atomic layer deposition (ALD) process for the first time. The silver was deposited from pulses of the organometallic precursor (hfac)Ag(1,5-COD) ((hexafluoroacetylacetonato)silver(I)(1,5-cyclooctadiene)) dissolved in a 0.1 M toluene solution. Catalytic oxidative dehydrogenation of the silver was achieved using intermittent pulses of propanol. The effect of substrate temperature on the size and distribution of nanoparticles has been investigated over the temperature range 110-150 degrees C. Transmission electron microscopy reveals that the nanoparticles consist of face centred cubic, facetted silver crystallites. The localized surface plasmon modes of the nanoparticles have been investigated using electron energy loss spectroscopy mapping. The distributions of plasmons within the ALD nanoparticles are comparable to those grown by solution methods. Both dipolar and quadrupolar resonant modes are observed, which is consistent with previous discrete dipole approximation models. Energy loss mapping of a loss feature at 8.1 eV reveals that it correlates with the bulk or volume region of the silver nanoparticles investigated here.

Thin films of ceria (CeO(2)) have many applications, and their synthesis by liquid-injection MOCVD (metal-organic chemical vapor deposition) or ALD (atomic layer deposition) requires volatile precursor compounds. Here we report the synthesis of a series of homoleptic and heteroleptic Ce(IV) complexes with donor-functionalized alkoxide ligands mmp (1-methoxy-2-methylpropan-2-olate), dmap (1-(dimethylamino)propan-2-olate), and dmop (2-(4,4-dimethyl-4,5-dihydrooxazol-2-yl)propan-2-olate) and their potential as precursors for MOCVD and ALD of CeO(2). New complexes were synthesized by alcohol exchange reactions with [Ce(OBu(t))(4)]. [Ce(mmp)(4)] and [Ce(dmap)(4)] were both found to be excellent precursors for liquid-injection MOCVD of CeO(2), depositing high purity thin films with very low carbon contamination, and both have a large temperature window for diffusion controlled growth (350-600 °C for [Ce(mmp)(4)]; 300-600 °C for [Ce(dmap)(4)]). [Ce(mmp)(4)] is also an excellent precursor for liquid-injection ALD of CeO(2) using H(2)O as oxygen source and demonstrates self-limiting growth from 150 to 350 °C. [Ce(dmap)(4)] has lower thermal stability than [Ce(mmp)(4)] and does not show self-limiting growth in ALD. Heteroleptic complexes show a tendency to undergo ligand redistribution reactions to form mixtures in solution and are unsuitable as precursors for liquid-injection CVD.

Essay: One of the largest CVD conferences ever held with over 230 papers and numerous posters was the combined fourteenth EUROCVD-14 and sixteenth international CVD conferences held in Paris are in the focus of this essay. The author does not only give an overview of sessions and highlights but also brings the atmosphere of the conference alive. EUROCVD-14 and CVD XVICommunication: Praseodymium oxide thin films are prepared using a new volatile precursor (for structure of precursor LiCl complex, see Figure) by liquid injection MOCVD. The oxide, a wide-bandgap (3.9 eV) and high-k material, which is currently being investigated as a possible alternative to SiO 2 films in silicon-based field-effect transistors, is deposited from [Pr(mmp) 3 ] (mmp = OCMe 2 CH 2 OMe) in the presence of oxygen over the temperature range 350±600 C.

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