Papers by Margrit Hanbücken
International Journal of Nanotechnology, Mar 20, 2015
ABSTRACT Electrochemistry can be used to fabricate different three dimensional objects on the nan... more ABSTRACT Electrochemistry can be used to fabricate different three dimensional objects on the nanometre scale. Porous anodic aluminium oxide (AAO) membranes with varying but controlled morphologies are used in several complementary experiments in physics and biology. The present paper gives a description of the membrane fabrication procedure and presents a selection of applications based on the use of the membranes as evaporation masks in crystal growth experiments, as masks in reactive ion etching experiments or as moulds to fabricate arrays of ordered polymer nanopillars. Applications in energy storage are also briefly mentioned. Finally the fabrication of TiO2 nanotubes (TNT) is described. Their anodic formation is very close to that of the AAO membranes and TNTs offer additional perspectives for applications.
Applied Surface Science, 2002
Concave-shaped surfaces have been prepared on 6H-SiC(0 0 0 1) substrates by exposing troughs, pre... more Concave-shaped surfaces have been prepared on 6H-SiC(0 0 0 1) substrates by exposing troughs, prepared by dimple grinding of flat SiC surfaces, to H 2 at high temperature. The morphological changes occurring under this H 2 etching were studied using scanning electron microscopy (SEM), atomic force microscopy (AFM) and ultrahigh vacuum scanning tunnelling microscopy (UHV-STM). Already after heating in H 2 at 1600 8C for 20 min, morphological changes are observed and heating in H 2 at 1700 8C for 15 min leads to the formation of alternating large and small terraces, separated by straight steps of 0.75 nm height on the flat parts of the substrate. A model is proposed which ascribes this bimodal terrace size distribution to the atomic structure of the SiC steps and to H diffusion on the terraces. For the same etching conditions less significant morphological variations were detected on the curved areas of the surface, where dimple grinding had been performed. The beginning of a considerable structural reorganisation of the concave-shaped surfaces was detected only when the etching temperature was increased to 1700 8C and the etching time to 1 h. Then, terrace steps with preferential edge orientation along the family of 1 1 2 0 Â Ã directions are formed in the concave-shaped areas, as observed by SEM.
Data Revues 16310748 Unassign S1631074812002871, Dec 28, 2012
ACS Applied Materials & Interfaces, 2015
Palladium nanoparticles are grown on TiO2 nanotubes by atomic layer deposition (ALD), and the res... more Palladium nanoparticles are grown on TiO2 nanotubes by atomic layer deposition (ALD), and the resulting three-dimensional nanostructured catalysts are studied for ethanol electrooxidation in alkaline media. The morphology, the crystal structure, and the chemical composition of the Pd particles are fully characterized using scanning and transmission electron microscopies, X-ray diffraction, and X-ray photoelectron spectroscopy. The characterization revealed that the deposition proceeds onto the entire surface of the TiO2 nanotubes leading to the formation of well-defined and highly dispersed Pd nanoparticles. The electrooxidation of ethanol on Pd clusters deposited on TiO2 nanotubes shows not only a direct correlation between the catalytic activity and the particle size but also a steep increase of the response due to the enhancement of the metal-support interaction when the crystal structure of the TiO2 nanotubes is modified by annealing at 450 °C in air.
Springer Series in Surface Sciences, 1988
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2002
ABSTRACT Regular hole patterns have been produced on vicinal Si(111) surfaces by optical lithogra... more ABSTRACT Regular hole patterns have been produced on vicinal Si(111) surfaces by optical lithography. Under heat treatment in ultrahigh vacuum, morphological rearrangements of the patterned surfaces occur. In situ light diffraction experiments were carried out during heat treatment to monitor the formation of the desired morphologies by an observation of the diffraction pattern. The surface morphology was characterized by different microscopy techniques after the heat treatment. Structured surfaces with periodic two-dimensional step arrangements and one-dimensional structures of atomically flat terraces uniformly separated by straight steps were obtained. The periodic structures extend over several μm. © 2002 American Vacuum Society.
Ultramicroscopy, 1983
Surface processes on bulk samples have been studied using an ultra high vacuum SEM, equipped with... more Surface processes on bulk samples have been studied using an ultra high vacuum SEM, equipped with a variety of surface-sensitive techniques. Recent studies of Stranski-Krastanov growth systems and the uses of a recently installed computerised data acquisition system are highlighted.
Surface Science, 2004
A concave-shaped surface has been prepared in a 6HSiC (0001) substrate by mechanical grinding. A... more A concave-shaped surface has been prepared in a 6HSiC (0001) substrate by mechanical grinding. As a consequence, the different crystallographic planes building up the 6HSiC polytype are cut under continuously changing polar angles in all azimuthal directions. ...
ECS Journal of Solid State Science and Technology, 2014
Atomic layer deposition (ALD) was used to synthesize highly-conformal titanium nitride thin films... more Atomic layer deposition (ALD) was used to synthesize highly-conformal titanium nitride thin films using both thermal activation at 250 • C and plasma activation at 200 • C. Tetrakisdimethylaminotitanium (TDMAT) and ammonia have been utilized as precursors. The evolutions of the thickness and the roughness of the films with the number of ALD cycles have been monitored by spectroscopic ellipsometry and atomic force microscopy, respectively. A slight difference has been observed between thermal and plasma-enhanced ALD TiN films. The chemical composition of the resulting layers for the two activation modes has been investigated by X-ray photoelectron spectroscopy. It indicates a partial oxidation of the film and it shows that the oxide content depends on the activation method and varies with the deposition temperature. The studies of both morphology and crystalline structure carried out by electron microscopy and X-ray diffraction have revealed homogeneous and polycrystalline films for the two activation processes. Electrical measurements have shown that the films grown by plasma-activation exhibit a higher conductivity. Finally, the TiN films were grown on high aspect ratio templates such as anodic aluminum oxide membranes. It demonstrates that highly-conformal TiN thin films can even be obtained by plasma-assisted process within such narrow three-dimensional nanostructures. That was unexpected.
International Journal of Nanotechnology, 2012
An overview over activities in nanoscience and nanotechnology in France and specifically the Prov... more An overview over activities in nanoscience and nanotechnology in France and specifically the Provence-Alpes-Côte d'Azur Region is given. Nanoscience activities are organised and funded in France by several institutions. A dedicated national programme, called C'Nano and which is coordinated by the French National Center for Scientific Research-CNRS, assures the animation. Project funding comes on the national level from the French Ministry for Higher Education and the French National Research Agency (ANR) or regionally from Universities and Regional and Local Councils. The activities and initiatives in nanoscience are accompanied by dedicated teaching and educational programmes.
Superlattices and Microstructures, 2004
Remerciements J'aimerais remercier par ces quelques lignes toutes les personnes qui, d'une manièr... more Remerciements J'aimerais remercier par ces quelques lignes toutes les personnes qui, d'une manière ou d'une autre, ont permis à cette thèse d'avoir lieu, tant d'un point de vue humain que d'un point de vue scientifique. Tout d'abord, je remercie tous les professeurs qui, au cours de mes études, m'ont donné les outils et les connaissances qui m'ont permis d'arriver jusqu'ici. Je pense surtout à Monsieur Bousquet qui m'a communiqué sa passion pour la Physique. MERCI ;o) La thèse est une période exigeante qui nécessite énormément d'investissement personnel dont on n'entrevoit rarement la fin, sauf le jour de la soutenance.. . Je tiens donc à exprimer ma reconnaissance à toutes les personnes bienveillantes qui m'ont aidée, soutenue, conseillée, encouragée et que j'ai eu la chance de rencontrer pendant cette aventure scientifique et humaine. Je tiens donc à remercier chaleureusement : Jean-François Bobo et Christophe Cardinaud d'avoir lu, complété et jugé ce travail, ainsi que Margrit Hanbücken, Bernard Agius et Bernard Mercey d'avoir accepté de faire partie du jury. Bernard Bartenlian de m'avoir proposé ce sujet de thèse qui n'aurait su mieux me convenir, d'avoir relu et corrigé ce manuscrit et de m'avoir défendu à plusieurs occasions. Xavier Le Roux de m'avoir fait partager son expérience, son expertise dans de nombreux domaines (lithographie, gravure, technologie salle blanche.. .) toujours avec sympathie, d'avoir relu et corrigé ce manuscrit et, surtout, de son Amitié.
Scientific reports, Jan 4, 2015
The growth of ultra-thin KCl films on the Si(111)7 × 7 reconstructed surface has been investigate... more The growth of ultra-thin KCl films on the Si(111)7 × 7 reconstructed surface has been investigated as a function of KCl coverage and substrate temperature. The structure and morphology of the films were characterized by means of scanning tunneling microscopy (STM) under ultra-high vacuum (UHV) conditions. Detailed analysis of the atomically resolved STM images of islands grown at room and high temperatures (400 K-430 K) revealed the presence of KCl(001) and KCl(111) islands with the ratio between both structures depending on the growth temperature. At room temperature, the growth of the first layer, which covers the initial Si(111)7 × 7 surface, contains double/triple atomic layers of KCl(001) with a small fraction of KCl(111) islands. The high temperature growth promotes the appearance of large KCl(111) areas, which are built up by three atomic layers. At room and high temperatures, flat and atomically well-defined ultra-thin KCl films can be grown on the Si(111)7 × 7 substrate. Th...
Surface Science, 1986
From the ,,erv hrst stages of adsorption, m the course ot the braid up of the interlaces th¢_ nob... more From the ,,erv hrst stages of adsorption, m the course ot the braid up of the interlaces th¢_ noble metals condensed on clean Sl(111) surta~_cs beha,,e qmte dlstmctv, el} A larg~, number ot investigations has been devoted to the characterization ot thcse ,,}stems which appear m man~ aspects as prototypes for further studies in semiconductor mt~_rfac¢ phi, sic,, Although ol increasing practLcal interest, the mtertaees of Cu, Ag and Au with Sl(ll)0) have been t.ompar,m,,el} much less studied in a fundamental v~av In this paper ~c re,,lew the knowledge acquired on these systems, adding new experimental results (electron spectroscopy and-nncroscop~) A comparison betx~cen noble-metal/%(100) and noble-metal/Sl(lll) interlace properties x~lll b~ included * Also UFR de Physique Um~,erslte de Pro'~ence
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Papers by Margrit Hanbücken