A low-cost platinum film deposited direct on glass substrate for electrochemical counter electrodes

AbstractThe preparation and characterization of platinum electrodes on glass substrates obtained by the Pechini method for a potential application as a counter electrode is presented in this paper. This method is based on the dissolution of citric acid (CA) and hexachloride platinum acid (H2PtCl6) in ethylene glycol (EG), and then calcinated in an appropriated temperature to produce the desired metallic film. Characterization was carried out by X-ray diffraction, scanning electron and atomic force microscopy and cyclic voltammetry. X-ray patterns of platinum on glass substrate showed the same features of the platinum bulk metal as well as its voltammetric profile. In order to determine the stability of the electrode, the electrode was subjected to 5000 voltammetric cycles and polarized at constant current of 100 mA cm−2 for at least 200 h, showing no considerable differences compared with the as synthesized electrode. Moreover, the main advantage of the electrode is the low cost (US$ 0.03 cm−2) of the prepared samples

Influence Of Ch4/h2 Reactive Ion Etching On The Deep Levels Of Si-doped Alxga1-xas (x=0.25)

We study the passivation and recovery of shallow and deep levels in Si-doped AlGaAs exposed to CH4/H2 and H2 reactive ion etching (RIE). The carrier concentration depth profile is determined by capacitance-voltage measurements. The activation energy to recover the silicon donors is found to be 1.1 eV for samples exposed to CH4/H2 RIE and 1.3 eV for samples exposed to H2 RIE. We study the behavior of DX centers in Si-doped AlGaAs layers after RIE exposure and subsequent thermal annealing by using deep level transient spectroscopy. For CH4TH2 RIE a new emission is detected at the high temperature side. We identify this emission as the DX3 center, which is assigned to a DX center with three aluminum atoms surrounding the Si donor. This DX center is only detected on the samples exposed to CH4/H2 RIE. We explain the formation of this deep level to the highly selective removal of Ga atoms in favor of Al atoms. Consequently Al-rich regions are created near the surface. © 1996 American Vacuum Society.14317731779Chevallier, J., Clerjaud, B., Pajot, B., (1991) Semiconductors and Semimetals, 34, p. 449. , Chap. 13Dautremont-Smith, W.C., (1988) Mater. Res. Soc. Symp. Proc., 104, p. 313Pearton, S.J., Dautremont-Smith, W.C., Chevallier, J., Tu, C.W., Cummings, K.D., (1986) J. Appl. Phys., 59, p. 2821Jalil, A., Chevallier, J., Pesant, J.C., Mostefaoui, R., Pajot, B., Murawala, P., Azoulay, R., (1987) Appl. Phys. Lett., 50, p. 439Chevallier, J., Pajot, B., Jalil, A., Mostefaoui, R., Rahbi, R., Boissy, M.C., (1988) Mater. Res. Soc. Symp. Proc., 104, p. 337Pavesi, L., Giannozzi, P., Reinhart, F.K., (1990) Phys. Rev. B, 42, p. 1864Pavesi, L., Giannozzi, P., (1991) Phys. Rev. B, 43, p. 2446Tavendale, A.J., Pearton, S.J., Williams, A.A., Alexiev, D., (1990) Appl. Phys. Lett., 56, p. 1457Yuan, M.H., Wang, L.P., Jin, S.X., Chen, J.J., Qin, G.G., (1991) Appl. Phys. Lett., 58, p. 925Srivastava, P.C., Chandra, S., Singh, U.P., (1991) Semicond. Sci. Technol., 6, p. 1126Cho, H.Y., Kim, E.K., Min, S., Chang, K.J., Lee, C., (1990) J. Appl. Phys., 68, p. 5077Zundel, T., Weber, J., (1989) Phys. Rev. B, 39, p. 13549Roos, G., Johnson, N.M., Herring, C., Harris, J.S., (1991) Appl. Phys. Lett., 56, p. 461Pearton, S.J., Abernathy, C.R., Lopata, J., (1991) Appl. Phys. Lett., 59, p. 3571Morrow, R.A., (1989) J. Appl. Phys., 66, p. 2973Cameron, N.I., Beaumont, S.P., Wilkinson, C.D.W., Johnson, N.P., Kean, A.H., Stanley, C.R., (1990) J. Vac. Sci. Technol. B, 8, p. 1966Cameron, N.I., Beaumont, S.P., Wilkinson, C.D.W., Johnson, N.P., Kean, A.H., Stanley, C.R., (1990) Microelectron. Eng., 11, p. 607Cheung, R., Thorns, S., McIntyre, I., Wilkinson, C.D.W., Beaumont, S.P., (1988) J. Vac. Sci. Technol. B, 6, p. 1911Jackson, G.S., Beberman, J., Feng, M.S., Hsieh, K.C., Holonyak Jr., N., Verdeyen, J., (1988) J. Appl. Phys., 64, p. 5175Dautremont-Smith, W.C., Nabity, J.C., Swaminathan, V., Stavola, M., Chevallier, J., Tu, C.W., Pearton, S.J., (1986) Appl. Phys. Lett., 49, p. 1098Jalil, A., Heurtel, A., Marfaing, Y., Chevallier, J., (1989) J. Appl. Phys., 66, p. 5854Nabity, J.C., Stavola, M., Lopata, J., Dautremont-Smith, W.C., Tu, C.W., Pearton, S.J., (1987) Appl. Phys. Lett., 50, p. 921Morrow, R.A., (1991) J. Appl. Phys., 69, p. 4306Chadi, D.J., Chang, K.J., (1988) Phys. Rev. Lett., 61, p. 873Chadi, D.J., Chang, K.J., (1988) Phys. Rev. B, 39, p. 10063Mooney, P.M., (1990) J. Appl. Phys., 67, pp. R1Chang, K.J., (1990) Proc. 20th Conference on Physics Semiconductor, 1, p. 787. , edited by E. M. Anastassakis and J. D. JoannopoulosCollot, P., Gaonach, C., (1990) Semicond. Sci. Technol., 5, p. 237Constantine, C., Johnson, D., Pearton, S.J., Chakrabarti, U.K., Emerson, A.B., Hobson, W.S., Kinsella, A.P., (1990) J. Vac. Sci. Technol. B, 8, p. 596Pearton, S.J., Chakrabarti, U.K., Hobson, W.S., (1989) J. Appl. Phys., 66, p. 2061Pearton, S.J., Abernathy, C.R., (1989) Appl. Phys. Lett., 55, p. 678Pearton, S.J., Hobson, W.S., Jones, K.S., (1989) J. Appl. Phys., 66, p. 5009Pereira, R., Van Hove, M., De Potter, M., Van Rossum, M., (1990) Electron. Lett., 26, p. 462Pereira, R., Van Hove, M., De Raedt, W., Jansen, Ph., Borghs, G., Jonckheere, R., Van Rossum, M., (1991) J. Vac. Sci. Technol. B, 9, p. 1978Chevallier, J., Dautremont-Smith, W.C., Tu, C.W., Pearton, S.J., (1985) Appl. Phys. Lett., 47, p. 108Hansen, W.L., Haler, E.E., Luke, P.N., (1982) IEEE Trans. Nucl. Sci., NS-29, p. 738Hall, R.N., (1984) IEEE Trans. Nucl. Sci., NS-31, p. 320Mooney, P.M., Theis, T.N., Wright, S.L., (1988) Appl. Phys. Lett., 53, p. 2546Mooney, P.M., Theis, T.N., Calleja, E., (1991) J. Electron. Mater., 20, p. 23Baba, T., Mizuta, M., Fujizawa, T., Yoshino, J., Kukimoto, H., (1989) Jpn. J. Appl. Phys., 28, pp. L891Morgan, T.N., (1991) J. Electron. Mater., 20, p. 6

Real-time remote sensing driven river basin modeling using radar altimetry

Many river basins have a weak in-situ hydrometeorological monitoring infrastructure. However, water resources practitioners depend on reliable hydrological models for management purposes. Remote sensing (RS) data have been recognized as an alternative to in-situ hydrometeorological data in remote and poorly monitored areas and are increasingly used to force, calibrate, and update hydrological models. <br><br> In this study, we evaluate the potential of informing a river basin model with real-time radar altimetry measurements over reservoirs. We present a lumped, conceptual, river basin water balance modeling approach based entirely on RS and reanalysis data: precipitation was obtained from the Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA), temperature from the European Centre for Medium-Range Weather Forecast's (ECMWF) Operational Surface Analysis dataset and reference evapotranspiration was derived from temperature data. The Ensemble Kalman Filter was used to assimilate radar altimetry (ERS2 and Envisat) measurements of reservoir water levels. The modeling approach was applied to the Syr Darya River Basin, a snowmelt-dominated basin with large topographical variability, several large reservoirs and scarce hydrometeorological data that is located in Central Asia and shared between 4 countries with conflicting water management interests. <br><br> The modeling approach was tested over a historical period for which in-situ reservoir water levels were available. Assimilation of radar altimetry data significantly improved the performance of the hydrological model. Without assimilation of radar altimetry data, model performance was limited, probably because of the size and complexity of the model domain, simplifications inherent in model design, and the uncertainty of RS and reanalysis data. Altimetry data assimilation reduced the mean absolute error of the simulated reservoir water levels from 4.7 to 1.9 m, and overall model RMSE from 10.3 m to 6.7 m. Model performance was variable for the different reservoirs in the system. The RMSE ranged from 10% to 76% of the mean seasonal reservoir level variation. <br><br> Because of its easy accessibility and immediate availability, radar altimetry lends itself to being used in real-time hydrological applications. As an impartial source of information about the hydrological system that can be updated in real time, the modeling approach described here can provide useful medium-term hydrological forecasts to be used in water resources management

Validity of the Generalized Second Law of Thermodynamics of the Universe Bounded by the Event Horizon in Holographic Dark Energy Model

In this letter, we investigate the validity of the generalized second law of thermodynamics of the universe bounded by the event horizon in the holographic dark energy model. The universe is chosen to be homogeneous and isotropic and the validity of the first law has been assumed here. The matter in the universe is taken in the form of non-interacting two fluid system- one component is the holographic dark energy model and the other component is in the form of dust.Comment: 8 page

Composition measurement of epitaxial Sc<inf>x</inf>Ga<inf>1-x</inf>N films

Four different methods for measuring the compositions of epitaxial ScxGa1-xN films were assessed and compared to determine which was the most reliable and accurate. The compositions of epitaxial ScxGa1-xN films with 0 ≤ x ≤ 0.26 were measured directly using Rutherford backscattering (RBS) and x-ray photoelectron spectroscopy (XPS), and indirectly using c lattice parameter measurements from x-ray diffraction and c/a ratio measurements from electron diffraction patterns. RBS measurements were taken as a standard reference. XPS was found to underestimate the Sc content, whereas c lattice parameter and c/a ratio were not reliable for composition determination due to the unknown degree of strain relaxation in the film. However, the Sc flux used during growth was found to relate linearly with x and could be used to estimate the Sc content

Kaluza-Klein Cosmology With Modified Holographic Dark Energy

We investigate the compact Kaluza-Klein cosmology in which modified holographic dark energy is interacting with dark matter. Using this scenario, we evaluate equation of state parameter as well as equation of evolution of the modified holographic dark energy. Further, it is shown that the generalized second law of thermodynamics holds without any constraint.Comment: 13 pages, accepted for publication in Gen. Relativ. Gravi

Endophytic and pathogenic Phyllosticta species, with reference to those associated with Citrus Black Spot

We investigated the identity and genetic diversity of more than 100 isolates belonging to Phyllosticta (teleomorph Guignardia), with particular emphasis on Phyllosticta citricarpa and Guignardia mangiferae s.l. occurring on Citrus. Phyllosticta citricarpa is the causal agent of Citrus Black Spot and is subject to phytosanitary legislation in the EU. This species is frequently confused with a taxon generally referred to as G. mangiferae, the presumed teleomorph of P. capitalensis, which is a non-pathogenic endophyte, commonly isolated from citrus leaves and fruits and a wide range of other hosts. DNA sequence analysis of the nrDNA internal transcribed spacer region (ITS1, 5.8S nrDNA, ITS2) and partial translation elongation factor 1-alpha (TEF1), actin and glyceraldehyde-3-phosphate dehydrogenase (GPDH) genes resolved nine clades correlating to seven known, and two apparently undescribed species. Phyllosticta citribraziliensis is newly described as an endophytic species occurring on Citrus in Brazil. An epitype is designated for P. citricarpa from material newly collected in Australia, which is distinct from P. citriasiana, presently only known on C. maxima from Asia. Phyllosticta bifrenariae is newly described for a species causing leaf and bulb spots on Bifrenaria harrisoniae (Orchidaceae) in Brazil. It is morphologically distinct from P. capitalensis, which was originally described from Stanhopea (Orchidaceae) in Brazil; an epitype is designated here. Guignardia mangiferae, which was originally described from Mangifera indica (Anacardiaceae) in India, is distinguished from the non-pathogenic endophyte, P. brazilianiae sp. nov., which is common on M. indica in Brazil. Furthermore, a combined phylogenetic tree revealed the P. capitalensis s.l. clade to be genetically distinct from the reference isolate of G. mangiferae. Several names are available for this clade, the oldest being P. capitalensis. These results suggest that endophytic, non-pathogenic isolates occurring on a wide host range would be more correctly referred to as P. capitalensis. However, more genes need to be analysed to fully resolve the morphological variation still observed within this clade

Magneto-optical trapping of bosonic and fermionic neon isotopes and their mixtures: isotope shift of the ^3P_2 to ^3D_3 transition and hyperfine constants of the ^3D_3 state of Ne-21

We have magneto-optically trapped all three stable neon isotopes, including the rare Ne-21, and all two-isotope combinations. The atoms are prepared in the metastable ^3P_2 state and manipulated via laser interaction on the ^3P_2 to ^3D_3} transition at 640.2nm. These cold (T = 1mK) and environmentally decoupled atom samples present ideal objects for precision measurements and the investigation of interactions between cold and ultracold metastable atoms. In this work, we present accurate measurements of the isotope shift of the ^3P_2 to ^3D_3 transition and the hyperfine interaction constants of the ^3D_3 state of Ne-21. The determined isotope shifts are (1625.9\pm0.15)MHz for Ne-20 to Ne-22, (855.7\pm1.0)MHz for Ne-20 to Ne-21, and (770.3\pm1.0)MHz for Ne-21 to Ne-22. The obtained magnetic dipole and electric quadrupole hyperfine interaction constants are A(^3D_3)= (-142.4\pm0.2)MHz and B(^3D_3)=(-107.7\pm1.1)MHz, respectively. All measurements give a reduction of uncertainty by about one order of magnitude over previous measurements