6 research outputs found
Competitive growth texture of pulse laser deposited VO2 nanostructures on a glass substrate
We report on the crystal structure and morphology of vanadium dioxide (VO2) nanostructures synthesized by pulsed laser deposition
on soda-lime glass substrates. The VO2 nanostructures exhibit sharp a-axis diffraction peaks, characteristic of the VO2 monoclinic phase,
which implies that highly a-axis textured VO2 was formed. A detailed description of the growth mechanisms and the substrate–film interaction
is given, and the characteristics of the electronic transition and hysteresis of the phase transition are described in terms of the
morphology and grain boundary structure. The sharpness of the transition and the hysteresis upon heating and cooling are found to
be strong functions of the crystal structure and microstructure (grain size and shape).UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, INRS (Canada), the ICTP-Trieste and the NANOAFNET.http://www.elsevier.com/locate/actamathb2014ai201
Effect of substrate temperature on the structure and the metal insulator transition in pulsed laser deposed V02\ films on soda lime glass
In this paper, we report the effect of soda lime substrate deposition temperature (Ts) on the crystal structure and
the metal insulator transition of VO2 thin films. Samples were deposited at substrate deposition temperature
ranging from 450 to 600 0C by pulsed-laser deposition and characterized by x-ray diffraction and UV-VIS
spectrophotometer. At a substrate temperature of 550°C, the VO2 (100) reflection dominate the spectrum
showing a change in crystalline grains orientation. The highest transition temperatures of 74 oC with the lowest
hysteresis width of 11 oC were obtained on the same sample grown at a substrate deposition temperature of 500
oC and also corresponding to the largest grains size of a value of 350 nm.http://link.springer.com/journal/125962016-03-31hb201
Interprétation des profils aux interfaces dans l'analyse par SIMS des multicouches métalliques
L'analyse des interfaces dans les multicouches métalliques à partir des profils SlMS obtenus en utilisant un faisceau primaire d'ions Cs+ et en détectant les ions moléculaires MCs+ (M étant l'élément à analyser) montre que dans de nombreux cas on observe une variation anormale du rendement ionique de MCs+ aux interfaces. Ce phénomène est lié d'une part à l'existence d'une couche interfaciale d'interdiffusion d'épaisseur nanométrique et d'autre part au rapport de densité des deux métaux constituant la multicouche. Quand le rapport de densité du métal lourd à celle du métal léger est inférieur à 1,4 cet anomalie de rendement ionique aux interfaces n'apparaît pas. C'est le cas des multicouches Ni-Fe, Co-Fe, Cu-Co, Nb-Fe, Fe-V, Ag-Co, Co-Zr, V-Ti, Al-Si pour lesquelles ce rapport varie de 1,13 à 1,36. Quand ce rapport est supérieur à 1,4 on observe une forte exaltation du signal MCs+ de l'élément léger et en général une atténuation du signal de l'élément lourd. C'est le cas des multicouches Ni-V, Ti-Al, Fe-Ti, Nb-Ti, Co-Ti, Ni-Ti, Cu-Ti, Cu-Al, Ni-Al, W-Ti, W-Al, Pt-Al, Pt-Si pour lesquelles ce rapport varie de 1,46 à 9,18. Ces résultats ont été confirmés par une étude comparative des intensités SIMS données par chacun des deux métaux à l'état pur et à l'état d'alliages homogènes de différentes compositions obtenues en couches minces par copulvérisation
Thermochromic nanocrystalline Au-VO2 composite thin films prepared by radiofrequency inverted cylindrical magnetron sputtering
Highly crystalline Au-VO2 nanocomposite thin films were prepared on Corning glass substrates by reactive radiofrequency inverted cylindrical magnetron sputtering (ICMS). It is a low cost potential coating technology for the production of large area uniform nanocomposite thin films exhibiting plasmonic properties. This paper reports the synthesis and feasibility of reliably reproduced high quality of Au-VO2 by ICMS. Structural, morphological, interfacial analysis and optical properties of synthesized Au-VO2
nanocomposite thin films are reported.The financial support from the African Laser Centre and Nanosciences African Network is gratefully acknowledged
Competitive growth texture of pulsed laser deposited vanadium dioxide nanostructures on a glass substrate
We report on the crystal structure and morphology of vanadium dioxide (VO2) nanostructures synthesized by pulsed laser deposition
on soda-lime glass substrates. The VO2 nanostructures exhibit sharp a-axis diffraction peaks, characteristic of the VO2 monoclinic phase,
which implies that highly a-axis textured VO2 was formed. A detailed description of the growth mechanisms and the substrate–film interaction
is given, and the characteristics of the electronic transition and hysteresis of the phase transition are described in terms of the
morphology and grain boundary structure. The sharpness of the transition and the hysteresis upon heating and cooling are found to
be strong functions of the crystal structure and microstructure (grain size and shape).UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, INRS (Canada), the ICTP-Trieste and the NANOAFNET.http://www.elsevier.com/locate/actamathb2014ai201