| 1. |
- Kaczmarski, J., et al.
(författare)
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Controlling In-Ga-Zn-O thin films transport properties through density changes
- 2016
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090. ; 608, s. 57-61
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Tidskriftsartikel (refereegranskat)abstract
- In the following study we investigate the effect of the magnetron cathode current (I-c) during reactive sputtering of In-Ga-Zn-O (a-IGZO) on thin-films nanostructure and transport properties. All fabricated films are amorphous, according to X-ray diffraction measurements. However, High Resolution Transmission Electron Microscopy revealed the a-IGZO fabricated at I-C = 70 mA to contain randomly-oriented nanocrystals dispersed in amorphous matrix, which disappear in films deposited at higher cathode current. These nanocrystals have the same composition as the amorphous matrix. One can observe that, while I-C is increased from 70 to 150 mA, the carrier mobility improves from mu(Hall) = 6.9 cm(2)/Vs to mu(Hall) = 9.1 cm(2)/Vs. Additionally, the increase of I-C caused a reduction of the depletion region trap states density of the Ru-Si-O/In-Ga-Zn-O Schottky barrier. This enhancement in transport properties is attributed to the greater overlapping of s-orbitals of the film-forming cations caused by increased density, evidenced by X-ray reflectivity, at a fixed chemical composition, regardless nanostructure of thin films. (C) 2016 Elsevier B.V. All rights reserved.
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| 2. |
- Kaczmarski, J., et al.
(författare)
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Transparent Ru–Si–O/In–Ga–Zn–O MESFETs on flexible polymer substrates
- 2018
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Ingår i: IEEE Transactions on Electron Devices. - 1557-9646 .- 0018-9383. ; 65:1, s. 129-135
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Tidskriftsartikel (refereegranskat)abstract
- With the development of novel device applications, e.g., in the field of Internet of Things or point-of-care personalized diagnostic systems, came an increased demand for MESFETs for fast and low-power consumption integrated circuits and active-matrix displays. In this paper, we present fabrication and characterization of transparent Ru–Si–O/In–Ga–Zn–O MESFETs on flexible substrates. The use of transparent conducting oxide, namely, Ru–Si–O, as Schottky gate electrode, allows for processing the devices at room temperature, enabling the utilization of such low-temperature substrates as polyethylene terephthalate foil and paper. It was shown that tuning the device geometry allows realization of transistors providing on-current up to 2 mA, while the highest on-to-off current ratio equals 2 × 105, with off-current below 1 nA, carrier mobility in the channel exceeds 9 cm2·V−1·s−1, and subthreshold swing is below 250 mV·decade−1
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| 3. |
- Åsberg, Dennis, 1988-, et al.
(författare)
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The importance of ion-pairing in peptide purification by reversed-phase liquid chromatography
- 2017
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Ingår i: Journal of Chromatography A. - : Elsevier. - 0021-9673 .- 1873-3778. ; 1496, s. 80-91
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption mechanism for three peptides was studied under overloaded conditions through adsorption isotherm measurements in the presence of an ion-pairing reagent, trifluoroacetic acid (TFA), on an end-capped C18-bonded stationary phase. The overall aim of the study was to obtain a better understanding of how the acetonitrile and the TFA fractions in the eluent affected the overloaded elution profiles and the selectivity between peptides using mechanistic modelling and multivariate design of experiments. When studying the effect of TFA, direct evidence for ion pair formation between a peptide and TFA in acetonitrile-water solutions was provided by fluorine-proton nuclear Overhauser NMR enhancement experiments and the adsorption of TFA on the stationary phase was measured by frontal analysis. The adsorption isotherms for each peptide were then determined by the inverse method at eight TFA concentrations ranging from 2.6 mM to 37.3 mM (0.02–0.29 vol-%) in isocratic elution. The equilibrium between the peptide ion and the peptide-TFA complex was modelled by coupling the mass-balance to reaction kinetics and determining separate adsorption isotherms for the two species. We found that a Langmuir isotherm described the elution profile of peptide-TFA complex well while the peptide ion was described by a bi-Langmuir adsorption isotherm since it exhibited strong secondary interactions. The elution profiles had an unfavorable shape at low TFA concentrations consisting of a spike in their front and a long tailing rear due to the secondary interactions for the peptide ion having very low saturation capacity. The acetonitrile dependence on the adsorption isotherms was studied by determination of adsorption isotherms directly from elution profiles obtained in gradient elution which enabled a broad acetonitrile interval to be studied. Here, it was found that the column saturation capacity was quickly reached at very low acetonitrile fractions and that there were significant variations in adsorption with the molecular weight. Finally, practical implications for method development are discussed based on an experimental design where gradient slope and TFA concentrations are used as factors. (c) 2017 Published by Elsevier B.V.
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