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Aswini Ghosh - One of the best experts on this subject based on the ideXlab platform.

  • Dynamics of lithium Ions in bismuthate glasses: Influence of strontium Ions
    Journal of Chemical Physics, 2006
    Co-Authors: A Dutta, Aswini Ghosh
    Abstract:

    The influence of strontium Ions on the relaxatIon dynamics of lithium Ions in bismuthate glasses has been investigated in the frequency range of 10Hzto2MHz. We have observed that the conductivity increases and the activatIon energy decreases with the increase of SrO content in the glass compositIons with fixed Li2O content. We have also observed that the conductivity increases and the activatIon energy decreases when Sr2+ Ions are replaced by Li+ Ions, keeping the glass former content fixed. We have shown that the estimated Mobile Ion concentratIon is almost independent of temperature and SrO content in the compositIons. We have further shown that a fractIon of total lithium Ions are Mobile for all glass compositIons. The results have been interpreted on the basis of the modificatIon of the bismuthate network by the additIon of SrO, which enhances the mobility of Li Ions, without altering the Mobile Li+ Ion concentratIon. We have also shown that the conductivity relaxatIon in these glasses is independent ...

  • Mixed Mobile Ion effect and relaxatIon dynamics in fluoride glasses
    Physics and Chemistry of Glasses, 2006
    Co-Authors: Surajit Ghosh, Aswini Ghosh
    Abstract:

    Fluoride glasses containing single alkali Ions as modifiers are fluoride and/or alkali Ion conductors, depending on the concentratIon and nature of alkali Ions. AdditIon of a second type of alkali Ions into a single alkali glass changes a variety of properties in a nonlinear fashIon. These changes are often referred to as the mixed Mobile Ion effect. We provide several evidences in favour of this effect in fluoride glasses where anIons also participate in the diffusIon processes in additIon to catIons, unlike in mixed alkali oxide glasses and crystals. A series of fluoride glass compositIons formed with ZrF 4 as the network formers and LiF and NaF as two alkali fluorides are synthesised. The electrical measurements are carried out using a precisIon RLC meter in the frequency range of 10 Hz-2 MHz in the temperature range from room temperature to just below glass transitIon temperature. A mixed Mobile Ion effect in these glasses has been observed. This phenomenon is associated with the low dimensIonality of the diffusIon pathways in the mixed alkali fluoride glasses compared to single alkali glasses. From different scaling approaches it is observed that the relaxatIon dynamics in these glasses is temperature independent.

  • Ion dynamics and mixed Mobile Ion effect in fluoride glasses
    Journal of Applied Physics, 2005
    Co-Authors: Surajit Ghosh, Aswini Ghosh
    Abstract:

    We report the Ionic relaxatIon and mixed Mobile Ion effect in 50ZrF4−10BaF2−10YF3−(30−x)LiF−xNaF fluoride glass series, where fluorine anIons participate in the diffusIon process in additIon to alkali catIons, unlike mixed alkali oxide glasses and crystals. By analyzing the Ion dynamics in the framework of a power-law model as well as modulus formalism we have observed mixed Mobile Ion effect in the dc conductivity and its activatIon energy, the crossover frequency and its activatIon energy, the conductivity relaxatIon frequency and its activatIon energy, and also in the decoupling index. We have correlated these phenomena with the fractal dimensIon of the conductIon pathways in the mixed alkali fluoride glasses compared to the single alkali glasses. We have shown that the relaxatIon dynamics in mixed alkali fluoride glasses is independent of temperature but dependent on glass compositIon.

  • Mixed Mobile Ion effect in fluorozincate glasses
    Journal of Physics: Condensed Matter, 2005
    Co-Authors: Surajit Ghosh, Aswini Ghosh
    Abstract:

    The mixed Mobile Ion effect has been investigated for the first time in zinc fluoride glasses where in additIon to alkali catIons fluorine anIons also participate in the diffusIon process, unlike mixed alkali oxide glasses. The minimum in the conductivity, conductivity relaxatIon frequency, crossover frequency and decoupling index indicates the existence of the mixed Mobile Ion effect in these fluoride glasses. It has been observed that the non-exponential parameter and the frequency exponent are independent of temperature. It has been established that alkali Ions and fluorine anIons exhibit lower dimensIonality of the conductIon pathways in mixed alkali zinc fluoride glasses than that in the single alkali lithium based zinc fluoride glasses while they are migrating. From the scaling of the conductivity spectra, it has been established that the relaxatIon dynamics in mixed alkali zinc fluoride glasses is independent of temperature and compositIon.

  • Mixed Mobile Ion effect in fluoride glasses
    Physical Review B, 2002
    Co-Authors: Surajit Ghosh, Aswini Ghosh
    Abstract:

    Certain Ionic materials containing dissimilar Mobile catIons exhibit the nonlinear behavior of diffusIon-related properties, called the mixed Mobile Ion effect. In these materials only catIons participate in the diffusIon process. In this paper we report on the mixed Mobile Ion effect in fluoride glasses, where anIons also participate in the diffusIon processes in additIon to catIons, unlike mixed alkali oxide glasses and crystals. We have provided several pieces of evidence in favor of this effect in fluoride glasses. This phenomenon was associated with the low dimensIonality of the diffusIon pathways in the mixed alkali fluoride glasses compared to single alkali glasses.

Shyam P. Murarka - One of the best experts on this subject based on the ideXlab platform.

  • Mobile Ion DetectIon in Organosiloxane Polymer Using Triangular Voltage Sweep
    Journal of The Electrochemical Society, 2002
    Co-Authors: A. Mallikarjunan, Shyam P. Murarka
    Abstract:

    The triangular voltage sweep (TVS) technique has been traditIonally used for Mobile Ion detectIon in gate oxides. In this paper, we present and discuss the results of TVS measurements on plasma enhanced chemical vapor deposited (PECVD) silicon oxide and a low dielectric constant hybrid organosiloxane polymer (HOSP). A variety of gate metals were studied to detect and separate Mobile Ion effects associated with the metal For the PECVD oxide, no peak was detected with Al gate metal, whereas a large peak was detected with Cu; allowing us to correlate the observed peak to Mobile copper Ions. TVS traces revealed no peak for Pt/HOSP capacitors but peaks were detected with Cu, Ta, and Al capacitors. Thus, the appearance of Mobile Ion peaks in the TVS traces correlated well with the previously published bias-temperature stressing (BTS) induced instability of these capacitors, where the Hatband voltage shifts during BTS were in the order Pt < Cu < Ta < Al, with no shift observed for Pt capacitors. The effects of temperature, voltage sweep rate, and bias hold time were also investigated for Al/HOSP and Cu/HOSP capacitors. Cu peaks were one to two orders of magnitude smaller than Al peaks under all conditIons investigated. It was concluded that the peaks originate from the gate metal.

Surajit Ghosh - One of the best experts on this subject based on the ideXlab platform.

  • Mixed Mobile Ion effect and relaxatIon dynamics in fluoride glasses
    Physics and Chemistry of Glasses, 2006
    Co-Authors: Surajit Ghosh, Aswini Ghosh
    Abstract:

    Fluoride glasses containing single alkali Ions as modifiers are fluoride and/or alkali Ion conductors, depending on the concentratIon and nature of alkali Ions. AdditIon of a second type of alkali Ions into a single alkali glass changes a variety of properties in a nonlinear fashIon. These changes are often referred to as the mixed Mobile Ion effect. We provide several evidences in favour of this effect in fluoride glasses where anIons also participate in the diffusIon processes in additIon to catIons, unlike in mixed alkali oxide glasses and crystals. A series of fluoride glass compositIons formed with ZrF 4 as the network formers and LiF and NaF as two alkali fluorides are synthesised. The electrical measurements are carried out using a precisIon RLC meter in the frequency range of 10 Hz-2 MHz in the temperature range from room temperature to just below glass transitIon temperature. A mixed Mobile Ion effect in these glasses has been observed. This phenomenon is associated with the low dimensIonality of the diffusIon pathways in the mixed alkali fluoride glasses compared to single alkali glasses. From different scaling approaches it is observed that the relaxatIon dynamics in these glasses is temperature independent.

  • Ion dynamics and mixed Mobile Ion effect in fluoride glasses
    Journal of Applied Physics, 2005
    Co-Authors: Surajit Ghosh, Aswini Ghosh
    Abstract:

    We report the Ionic relaxatIon and mixed Mobile Ion effect in 50ZrF4−10BaF2−10YF3−(30−x)LiF−xNaF fluoride glass series, where fluorine anIons participate in the diffusIon process in additIon to alkali catIons, unlike mixed alkali oxide glasses and crystals. By analyzing the Ion dynamics in the framework of a power-law model as well as modulus formalism we have observed mixed Mobile Ion effect in the dc conductivity and its activatIon energy, the crossover frequency and its activatIon energy, the conductivity relaxatIon frequency and its activatIon energy, and also in the decoupling index. We have correlated these phenomena with the fractal dimensIon of the conductIon pathways in the mixed alkali fluoride glasses compared to the single alkali glasses. We have shown that the relaxatIon dynamics in mixed alkali fluoride glasses is independent of temperature but dependent on glass compositIon.

  • Mixed Mobile Ion effect in fluorozincate glasses
    Journal of Physics: Condensed Matter, 2005
    Co-Authors: Surajit Ghosh, Aswini Ghosh
    Abstract:

    The mixed Mobile Ion effect has been investigated for the first time in zinc fluoride glasses where in additIon to alkali catIons fluorine anIons also participate in the diffusIon process, unlike mixed alkali oxide glasses. The minimum in the conductivity, conductivity relaxatIon frequency, crossover frequency and decoupling index indicates the existence of the mixed Mobile Ion effect in these fluoride glasses. It has been observed that the non-exponential parameter and the frequency exponent are independent of temperature. It has been established that alkali Ions and fluorine anIons exhibit lower dimensIonality of the conductIon pathways in mixed alkali zinc fluoride glasses than that in the single alkali lithium based zinc fluoride glasses while they are migrating. From the scaling of the conductivity spectra, it has been established that the relaxatIon dynamics in mixed alkali zinc fluoride glasses is independent of temperature and compositIon.

  • Mixed Mobile Ion effect in fluoride glasses
    Physical Review B, 2002
    Co-Authors: Surajit Ghosh, Aswini Ghosh
    Abstract:

    Certain Ionic materials containing dissimilar Mobile catIons exhibit the nonlinear behavior of diffusIon-related properties, called the mixed Mobile Ion effect. In these materials only catIons participate in the diffusIon process. In this paper we report on the mixed Mobile Ion effect in fluoride glasses, where anIons also participate in the diffusIon processes in additIon to catIons, unlike mixed alkali oxide glasses and crystals. We have provided several pieces of evidence in favor of this effect in fluoride glasses. This phenomenon was associated with the low dimensIonality of the diffusIon pathways in the mixed alkali fluoride glasses compared to single alkali glasses.

A. Mallikarjunan - One of the best experts on this subject based on the ideXlab platform.

  • Mobile Ion DetectIon in Organosiloxane Polymer Using Triangular Voltage Sweep
    Journal of The Electrochemical Society, 2002
    Co-Authors: A. Mallikarjunan, Shyam P. Murarka
    Abstract:

    The triangular voltage sweep (TVS) technique has been traditIonally used for Mobile Ion detectIon in gate oxides. In this paper, we present and discuss the results of TVS measurements on plasma enhanced chemical vapor deposited (PECVD) silicon oxide and a low dielectric constant hybrid organosiloxane polymer (HOSP). A variety of gate metals were studied to detect and separate Mobile Ion effects associated with the metal For the PECVD oxide, no peak was detected with Al gate metal, whereas a large peak was detected with Cu; allowing us to correlate the observed peak to Mobile copper Ions. TVS traces revealed no peak for Pt/HOSP capacitors but peaks were detected with Cu, Ta, and Al capacitors. Thus, the appearance of Mobile Ion peaks in the TVS traces correlated well with the previously published bias-temperature stressing (BTS) induced instability of these capacitors, where the Hatband voltage shifts during BTS were in the order Pt < Cu < Ta < Al, with no shift observed for Pt capacitors. The effects of temperature, voltage sweep rate, and bias hold time were also investigated for Al/HOSP and Cu/HOSP capacitors. Cu peaks were one to two orders of magnitude smaller than Al peaks under all conditIons investigated. It was concluded that the peaks originate from the gate metal.

A Di Carlo - One of the best experts on this subject based on the ideXlab platform.

  • on the relatIon between Mobile Ion kinetics device design and doping in double catIon perovskite solar cells
    Applied Physics Letters, 2021
    Co-Authors: Ali Sehpar Shikoh, A Y Polyakov, P Gostishchev, Danila Saranin, I V Shchemerov, S I Didenko, A Di Carlo
    Abstract:

    ContributIon of Mobile Ions to current transport in double catIon FA1−xCsxPbI3 p–i–n solar cell structures with NiOx hole transport layers and electron transport layers (ETLs) formed by Phenyl-C61-butyric acid methyl ester (PCBM) or C60 was studied by means of our previously developed suite of techniques comprising admittance spectroscopy, Deep Levels Transient Spectroscopy with standard (DLTS) and reversed (RDLTS) sequence of biasing/pulsing, and Photoinduced Open-Circuit Voltage Voc Spectroscopy (PIVTS). These studies show that the amplitudes of mirror-like peaks in DLTS/RDLTS, the hallmark of Mobile Ions, strongly decrease when switching from PCBM to C60 and further decrease with the additIon of Cl to the growth solutIon. A similar effect is observed in PIVTS spectra monitoring changes in long-time open circuit Voc relaxatIons with temperature. The activatIon energies of peaks in DLTS, PIVTS, and low-frequency admittance spectra are similar to each other. The results indicate that switching the ETL type from PCBM to C60 and adding Cl in the perovskite ink for improved crystallizatIon result in alleviating adverse effects of Mobile Ions, which correlates with observed changes in solar cell performance and reliability. Possible reasons for the described phenomena will be discussed.