Thulium and ytterbium-doped titania thin films deposited by MOCVD

In this study we synthesized thin films of titanium oxide doped with thulium and/or ytterbium to modify the incident spectrum on the solar cells. This could be achieved either by photoluminescence up-converting devices, or down-converting devices. As down-converter thin films our work deals with thulium and ytterbium-doped titanium dioxide. Thulium and ytterbium will act as sensitizer and emitter, respectively. The rare-earth doped thin films are deposited by aerosol-assisted MOCVD using organo-metallic precursors such as titanium dioxide acetylacetonate, thulium and ytterbium tetramethylheptanedionate solved in different solvents. These films have been deposited on silicon substrates under different deposition conditions (temperature and dopant concentrations for example). Adherent films have been obtained for deposition temperatures ranging from 300{\deg}C to 600{\deg}C. The deposition rate varies from 0.1 to 1 \mu m/h. The anatase phase is obtained at substrate temperature above 400{\deg}C. Further annealing is required to exhibit luminescence and eliminate organic remnants of the precursors. The physicochemical and luminescent properties of the deposited films were analyzed versus the different deposition parameters and annealing conditions. We showed that absorbed light in the near-UV blue range is re-emitted by the ytterbium at 980 nm and by a thulium band around 800 nm.Comment: 4 pages, 6 figures, proceedin

Expert consensus on monitoring antimicrobial stewardship in French nursing homes using assessed reimbursement database indicators

Objectives Monitoring the appropriateness of antibiotic prescriptions with indicators based on reimbursement data is required to guide antibiotic stewardship (AMS) interventions in nursing homes (NHs). Quantity metrics (QMs) monitor the volume of prescriptions while proxy indicators (PIs) reflect the appropriateness of antibiotic use. Our objectives were: (i) to provide a relevant consensual set of indicators to be used in French NHs; and (ii) to assess the feasibility of their implementation at the national and local scale. Methods Nine French professional organizations implicated in AMS in NHs were asked to nominate at least one member to create a national expert panel of 20 physicians. Twenty-one recently published QMs and 11 PIs were assessed by the expert panel. Indicators were evaluated using a RAND-modified Delphi procedure comprising two online surveys and a videoconference meeting. Indicators were kept in the final list if >70% of stakeholders validated their relevance for estimating the volume (QMs) and appropriateness (PIs) of prescriptions. Results Of the 21 QM indicators submitted to the panel, 14 were selected, describing the consumption of antibiotics overall (n = 3), broad-spectrum (n = 6) and second-line antibiotics (n = 2). The three remaining QMs evaluated the route of administration (n = 1) and urine culture prescriptions (n = 2). Ten PIs (six modified, two rejected, one new) were selected to assess the appropriateness of prescriptions for urinary tract infections (n = 2), seasonal variations in prescriptions (n = 2), repeated prescriptions of fluoroquinolones (n = 1), cephalosporins’ route of administration (n = 1), duration of treatment (n = 1), rate of second-line antibiotics (n = 1), co-prescriptions with non-steroidal anti-inflammatory drugs (n = 1), and flu vaccine coverage (n = 1). The panel was in favour of using these indicators for regional and facility level AMS programmes (91%), feedback to NH prescribers (82%), benchmarking by health authorities (55%) and public reporting at the facility level (9%). Conclusions This consensual list of indicators, covering a wide range of frequent clinical situations, may be used as part of the French national AMS strategy for monitoring antibiotic prescriptions in NHs at the national and local levels. Regional AMS networks might manage this selected list to guide personalized action plans with concrete objectives of reducing the quantity and improving the quality of antibiotic prescriptions

Deposition conditions for the growth of textured ZnO thin films by aerosol CVD process

The crystalline orientation of ZnO thin films deposited by an aerosol CVD process is studied with regard to the experimental conditions. The quality of the C-axis oriented growth depended on the substrate temperature, on the deposition rate and also on the hygrometric degree of the carrier gas. The quality of the gold sublayer influenced also the quality of the ZnO textured growth. Under a dry gas mixture N2-O2 at 495°C and with a deposition rate of 35Å/mn, the texture ratio was less than -3.5 and the misorientation σ002 was less than 1.6°

ELECTROREFLECTANCE AND BAND STRUCTURE OF ZnSiAs2-xPx ALLOYS

We verify the Vegard law for ZnSiAs2-xPx solid solution. We follow by electroreflectance the Γ15 → Γ1 transitions in the entire range of composition and give the direct threshold Γ1 → Γ6 = 3.42 eV for ZnSiP2. From the quasicubic model we obtain the crystal field and the spin-orbit splitting which are compared with theory

ELECTROREFLECTANCE AND BAND STRUCTURE OF ZnSiAs2-xPx ALLOYS

L'étude de la solution solide ZnSiAs2-xPx montre que la variation des paramètres a et c en fonction de la composition suit la loi de Végard. L'étude de cette solution solide par électroréflectance, à température ambiante, a permis d'établir l'évolution des transitions directes en fonction de la composition et de déterminer le gap de ZnSiP2 : Γ1 → Γ6 = 3,42 eV. Les valeurs expérimentales du champ cristallin et de l'éclatement spin-orbite obtenues à partir du modèle quasi cubique sont en bon accord avec les valeurs théoriques.We verify the Vegard law for ZnSiAs2-xPx solid solution. We follow by electroreflectance the Γ15 → Γ1 transitions in the entire range of composition and give the direct threshold Γ1 → Γ6 = 3.42 eV for ZnSiP2. From the quasicubic model we obtain the crystal field and the spin-orbit splitting which are compared with theory

Elaboration par le procédé pyrosol de couches minces texturées de ZnO pour la réalisation de microcapteurs

The crystalline orientation of ZnO thin films deposited by an aerosol CVD process is studied with regard to the experimental conditions. The quality of the $C$-axis oriented growth depended on the substrate temperature, on the deposition rate and also on the hygrometric degree of the carrier gas. The quality of the gold sublayer influenced also the quality of the ZnO textured growth. Under a dry gas mixture N$_2$-O$_2$ at 495 $^{\circ}$C and with a deposition rate of 35 Å/mn, the texture ratio was less than -3.5 and the misorientation of the 002 line was less than 1.6$^{\circ}$.L'orientation cristalline de couches minces de ZnO élaborées par le procédé pyrosol est étudiée en fonction des conditions de dépôt. La qualité de la texture selon l'axe $C$ dépend de la température du substrat, de la vitesse de dépôt, du degré d'hygrométrie du gaz vecteur et également de la qualité de la sous-couche chrome/or. Pour des dépôts réalisés avec un mélange pur et sec d'azote et d'oxygène à 495 $^{\circ}$C et pour une vitesse de dépôt de 35 Å/mn, le rapport de texture est inférieur à -3,5 et la désorientation de la raie 002 est inférieure à 1,6$^{\circ}$

Epitaxial growth of Vanadium oxide VO2 by aerosol assisted MOCVD

National audienc