A complementary suite of in situ synchrotron X-ray techniques is used to investigate both structural and chemical evolution during ZnO growth by atomic layer deposition. Focusing on the first 10 cycles of growth, we observe that the structure formed during the coalescence stage largely determines the overall microstructure of the film. Furthermore, by comparing ZnO growth on silicon with a native oxide with that on Al2O3(001), we find that even with lattice-mismatched substrates and low deposition temperatures, the crystalline texture of the films is dependent strongly on the nature of the interfacial bonds.

This paper presents the upgraded 'In situ growth of Nanoscructures on Surfaces' (INS) endstation of the InterFace beamline IF-BM32 at the European Synchrotron Radiation Facility (ESRF). This instrument, originally designed to investigate the structure of clean surfaces/interfaces/thin-films by surface X-ray diffraction, has been further developed to investigate the formation and evolution of nanostructures by combining small-and wide-angle X-ray scattering methodologies, i.e. grazing-incidence small-angle X-ray scattering (GISAXS) and grazing-incidence X-ray diffraction (GIXD). It consists of a UHV chamber mounted on a z-axis type goniometer, equipped with residual gas analysis, reflection high-energy electron diffraction (RHEED) and Auger electron spectroscopy (AES) to complete the X-ray scattering investigations. The chamber has been developed so as up to eight sources of molecular beam epitaxy (MBE) can be simultaneously mounted to elaborate the nanostructures. A chemical vapor deposition (CVD) set-up has been added to expand the range of growing possibilities, in particular to investigate in situ the growth of semiconductor nanowires. This setup is presented in some detail, as well as the first in situ X-ray scattering measurements during the growth of silicon nanowires.

Nucleation of GaN nanowires grown by plasma-assisted molecular beam epitaxy is studied through a combination of two in situ tools: grazing incidence x-ray diffraction and reflection high energy electron diffraction. Growth on bare Si(111) and on AlN/Si(111) is compared. A significantly larger delay at nucleation is observed for nanowires grown on bare Si(111). The difference in the nucleation delay is correlated to a dissimilarity of chemical reactivity between Al and Ga with nitrided Si(111).

It will be reported about the effect of the sputtering gases, Ar and Xe, on FePt clusters formation by magnetron sputtering deposition at high working pressures. All layers, with bulk equivalent thicknesses between 3 to 5 nm, were realized at RT by a sequential layer by layer deposition or a co-deposition of Fe and Pt. After rapid thermal annealing at 500 °C, the highest L10 fraction was found using Xe as sputtering gas: Xe decreases the transformation activation energy and therefore, reduces the critical thickness necessary to obtain the high anistropic ferromagnetic phase. Ar assisted growths lead to FePt clusters in the L10 phase only if the sequential layer deposition is used, whereas for Xe no differences in the deposition techniques were observed.

The A1→L10 phase transition of Fe50Pt50 films, deposited at room-temperature on amorphous SiO2 by dc magnetron co-sputtering at 0.3Pa, was studied with in-situ X-ray diffraction. An almost complete transition characterized by a long-range order parameter S>0.8 is obtained already after a heat treatment at (320±20)°C. A post-deposition He ion irradiation (50keV, 1×1015−3×1016cm−2) does not further reduce the transition temperature. Theoretical calculations reveal that, due to the negligible thermalization of the sputtered atoms and reflected ions in the plasma, a considerable fraction of energetic ions and atoms meet the substrate surface. The low transition temperature is explained by the impact of energetic ions and atoms which provoke significant adatom mobility and a decrease of the activation energy for atomic reordering by vacancies. Consequently, using deposition parameters leading to a strong thermalized plasma, the FePt films showed an increase of the transition temperature up to 400°C, a lower S-value (S≅0.6) and a reduced coercivity.

Using synchrotron x-ray diffraction and reflectivity, we studied the transition from the paramagnetic NiMn phase to the chemically ordered, antiferromagnetic L10 phase of NiMn∕Fe19Ni81 thin films deposited on a Si∕SiO2 substrate as a function of the annealing temperature. The transformation to a dominating L10-ordered NiMn film takes place between 300 and 400°C irrespective of the irradiation. This is also consistent with magnetization reversal measurements of the corresponding permalloy layers. The benefit of the ion irradiation is a reduction of the mosaicity for both the NiMn and the permalloy film, and a smoothening of internal interfaces.

We investigate the effects of room-temperature irradiation of Au and Ge nanoislands grown on Si. Our studies show the formation of Au-Ge alloy phase within the islands and wetting of the substrate. High-resolution transmission electron microscopy along with synchrotron radiation-based x-ray reflectivity and grazing incidence x-ray diffraction measurements were performed to characterize the irradiation-induced changes brought into the sequentially deposited Au and Ge island thin films. The results are attributed to the recoil implantation and the transient melting of the nanoislands followed by the formation of crystalline alloy phase.

The evolution of ion beam synthesized Co and Ge nanoclusters into a SiO2 matrix during annealing processes has been investigated by X-ray diffraction and transmission electron microscopy. Remarkable differences have been found between Ge and Co clusters behaviour. For Ge implanted SiO2 films, a clear influence of near-surface Ge oxidation and nanoclusters melting has been established. Annealing at temperatures around 1000°C leads to the formation of small (diameter ∼5nm) nanocrystals. Classical Ostwald ripening mainly drives the clusters thermodynamical growth. On the contrary, for Co-implanted SiO2 films, a jump-like transition in nanoclusters evolution has been established at about 800°C. A homogenous distribution of small (diameter ∼4nm) amorphous clusters is transformed into a bimodal clusters profile, characterised by large (diameter between 20 and 40nm) nanocrystals near the surface and a region of smaller clusters (diameter ∼7nm) in depth. During Co nanoclusters formation the influence of nanoclusters melting can be neglected.

Indium tin oxide films produced by reactive middle frequency magnetron sputtering were annealed in a vacuum. The electrical and optical properties of the film have been studied in situ along with direct characterization of the crystalline structure. Even in the amorphous state, the film resistivity significantly decreases with increasing temperature due to a free-electron density enhancement, likely by the generation of oxygen vacancies. A rapid crystallization within the temperature range of 250–280°C leads to a further decrease of the resistivity due to Sn donor activation. The resistivity and the optical properties depend nonlinearly on the crystalline fraction.

Metal-Organic Deposition (MOD) technique has been used for the first time, in the spray version, to obtain thin and thick films of BSCCO on substrates like MgO and Ag and, in the dipping version, to deposit YBCO thick films directly on a thin Ag wire. Diffraction data show that BSCCO films are textured and oriented with their normal axis along the [001] direction. Electron microprobe data confirm a strong presence of (2212) modification of BSCCO. The YBCO/Ag wire is very uniform, as confirmed by SEM micrographs, and shows a transition temperature around 90 K. Thick films and platelets of YBCO have been also prepared by metalorganic solution spraying and by using a commercial microwave oven in the last annealing stage, reducing the duration of this step from several hours to about 65 minutes. YBCO samples show good stoichiometry, a very smooth surface morphology and transition temperatures, as measured by a.c. susceptometry at low magnetic fields, which are around 90 K. Films, deposited on MgO, are oriented with their growth axis along the [005] direction and, if deposited on SrTiO3, along the [006] direction. Physical, chemical, structural and morphological properties of these HTSC samples obtained by MOD are presented and discussed, with the conclusion that this technique, which is simple, flexible, suitable for large surface areas, for ribbons and for wires, has achieved a good stage of maturity.

Contact DermatitisVolume 11, Issue 3 p. 190-190 Allergic dermatitis from etofenamate N. Balato, N. Balato Department of Dermatology, 2nd Faculty of Medicine and Surgery, University of Naples, Via Pansini 5,80131 Naples, ItalySearch for more papers by this authorG. Lembo, G. Lembo Department of Dermatology, 2nd Faculty of Medicine and Surgery, University of Naples, Via Pansini 5,80131 Naples, ItalySearch for more papers by this authorV. Cantelli, V. Cantelli Department of Dermatology, 2nd Faculty of Medicine and Surgery, University of Naples, Via Pansini 5,80131 Naples, ItalySearch for more papers by this authorF. Ayala, F. Ayala Department of Dermatology, 2nd Faculty of Medicine and Surgery, University of Naples, Via Pansini 5,80131 Naples, ItalySearch for more papers by this author N. Balato, N. Balato Department of Dermatology, 2nd Faculty of Medicine and Surgery, University of Naples, Via Pansini 5,80131 Naples, ItalySearch for more papers by this authorG. Lembo, G. Lembo Department of Dermatology, 2nd Faculty of Medicine and Surgery, University of Naples, Via Pansini 5,80131 Naples, ItalySearch for more papers by this authorV. Cantelli, V. Cantelli Department of Dermatology, 2nd Faculty of Medicine and Surgery, University of Naples, Via Pansini 5,80131 Naples, ItalySearch for more papers by this authorF. Ayala, F. Ayala Department of Dermatology, 2nd Faculty of Medicine and Surgery, University of Naples, Via Pansini 5,80131 Naples, ItalySearch for more papers by this author First published: August 1984 https://doi.org/10.1111/j.1600-0536.1984.tb00973.xCitations: 10AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume11, Issue3August 1984Pages 190-190 RelatedInformation