References of "Redinger, Alex 50026033"
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See detailRadiative recombination from localized states in CZT(S,Se) investigated by combined PL and TRPL at low temperatures
Kretzschmar, Steffen; Levcenco, Sergej; Just, Justus et al

in IEEE PVSEC proceedings (2016)

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See detailOvercoming the Voc limitation of CZTSe solar cells
Risch, L.; Vauche, L.; Redinger, Alex UL et al

in IEEE (2016)

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See detailIntragrain charge transport in kesterite thin films-Limits arising from carrier localization
Hempel, Hannes; Redinger, Alex UL; Repins, Ingrid et al

in JOURNAL OF APPLIED PHYSICS (2016), 120(17),

Intragrain charge carrier mobilities measured by time-resolved terahertz spectroscopy in state of the art Cu2ZnSn(S,Se)(4) kesterite thin films are found to increase from 32 to 140 cm(2) V-1 s(-1) with ... [more ▼]

Intragrain charge carrier mobilities measured by time-resolved terahertz spectroscopy in state of the art Cu2ZnSn(S,Se)(4) kesterite thin films are found to increase from 32 to 140 cm(2) V-1 s(-1) with increasing Se content. The mobilities are limited by carrier localization on the nanometer-scale, which takes place within the first 2 ps after carrier excitation. The localization strength obtained from the Drude-Smith model is found to be independent of the excited photocarrier density. This is in accordance with bandgap fluctuations as a cause of the localized transport. Charge carrier localization is a general issue in the probed kesterite thin films, which were deposited by co-evaporation colloidal inks, and sputtering followed by annealing with varying Se/S contents and yield 4.9\%-10.0 efficiency in the completed device. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). [less ▲]

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See detailPhotoluminescence studies in epitaxial CZTSe thin films
Sendler, Jan UL; Thevenin, Maxime UL; Werner, Florian UL et al

in Journal of Applied Physics (2016), 120

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See detailQuantitative PL Imaging of Thin Film Solar Cells - Potential and Pitfalls
Redinger, Alex UL; Kretzschmar, Steffen; Unold, Thomas Ieee

in IEEE PVSEC proceedings (2016)

Photoluminescence imaging as well as quantitative photoluminescence spectroscopy has been successfully applied to different solar cell materials, such as crystalline silicon and polycrystalline Cu(In, Ga ... [more ▼]

Photoluminescence imaging as well as quantitative photoluminescence spectroscopy has been successfully applied to different solar cell materials, such as crystalline silicon and polycrystalline Cu(In, Ga) Se-2. These methods can be used to investigate spatial inhomogeneities as well as for the contactless determination of quasi-Fermi level splittings, which are related to the open-circuit voltage in finished photovoltaic devices. The theory underlying the analysis of quantitative PL imaging is found to work reliably for more ideal semiconductors such as silicon, but can pose substantial problems for the more non-ideal semiconductors such as kesterite-type materials, where both the optical properties as well as the recombination process may vary widely from sample to sample. In this contribution we will evaluate different approaches to analyse quantitative PL imaging and discuss the potential pitfalls incurred, especially when the actual sample temperature during the measurement is not properly taken into account. [less ▲]

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See detailHighly conductive ZnO films with high near infrared transparency
Hala, Matej UL; Fujii, Shohei; Redinger, Alex UL et al

in Progress in Photovoltaics: Research and Applications (2015)

We present an approach for deposition of highly conductive nominally undoped ZnO films that are suitable for the n-type window of low band gap solar cells. We demonstrate that low-voltage radio frequency ... [more ▼]

We present an approach for deposition of highly conductive nominally undoped ZnO films that are suitable for the n-type window of low band gap solar cells. We demonstrate that low-voltage radio frequency (RF) biasing of growing ZnO films during their deposition by non-reactive sputtering makes them as conductive as when doped by aluminium (ρ≤1·10−3Ω cm). The films prepared with additional RF biasing possess lower free-carrier concentration and higher free-carrier mobility than Al-doped ZnO (AZO) films of the same resistivity, which results in a substantially higher transparency in the near infrared region (NIR). Furthermore, these films exhibit good ambient stability and lower high-temperature stability than the AZO films of the same thickness. We also present the characteristics of Cu(InGa)Se2, CuInSe2 and Cu2ZnSnSe4-based solar cells prepared with the transparent window bilayer formed of the isolating and conductive ZnO films and compare them to their counterparts with a standard ZnO/AZO bilayer. We show that the solar cells with nominally undoped ZnO as their transparent conductive oxide layer exhibit an improved quantum efficiency for λ > 900 nm, which leads to a higher short circuit current density JSC. This aspect is specifically beneficial in preparation of the Cu2ZnSnSe4 solar cells with band gap down to 0.85 eV; our champion device reached a JSC of nearly 39 mAcm−2, an open circuit voltage of 378 mV, and a power conversion efficiency of 8.4 %. [less ▲]

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See detailDifferent Bandgaps in Cu2ZnSnSe4: A High Temperature Coevaporation Study
Redinger, Alex UL; Sendler, Jan UL; Djemour, Rabie et al

in IEEE Journal of Photovoltaics (2015), 5(2), 641-648

We present a high-temperature Cu2ZnSnSe4 coevaporation study, where solar cells with a power conversion efficiency of 7.1 have been achieved. The process is monitored with laser light scattering in order ... [more ▼]

We present a high-temperature Cu2ZnSnSe4 coevaporation study, where solar cells with a power conversion efficiency of 7.1 have been achieved. The process is monitored with laser light scattering in order to follow the incorporation of the Sn into the film. We observe the segregation of ZnSe at the Mo/CZTSe interface. Optical analysis has been carried out with photoluminescence and spectrophotometry. We observe strong band tailing and a bandgap, which is significantly lower than in other reported efficient CZTSe absorbers. The photoluminescence at room temperature is lower than the bandgap due to the existence of a large quantity of tail states. Finally, we present effects of low-temperature postannealing of the absorbers on ordering of the Cu/Zn atoms in CZTSe and solar cell parameters. We observe strong changes in all solar cell parameters upon annealing. The efficiency of the annealed devices is significantly reduced, although ordering is improved compared with ones made from nonannealed absorbers. [less ▲]

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See detailEpitaxial Cu2ZnSnSe4 thin films and devices
Redinger, Alex UL; Groiss, Heiko; Sendler, Jan UL et al

in THIN SOLID FILMS (2015), 582

Epitaxial Cu2ZnSnSe4 (CZTSe) thin films have been grown via high temperature coevaporation on GaAs(001). Electron backscattering diffraction confirms epitaxy in a wide compositional range. Different ... [more ▼]

Epitaxial Cu2ZnSnSe4 (CZTSe) thin films have been grown via high temperature coevaporation on GaAs(001). Electron backscattering diffraction confirms epitaxy in a wide compositional range. Different secondary phases are present in the epitaxial layer. The main secondary phases are Cu2SnSe3 and ZnSe which grow epitaxially on top of the CZTSe. Transmission electron microscopy measurements show that the epitaxial CZTSe grows predominantly parallel to the c-direction. Epitaxial CZTSe solar cells with a maximum power conversion efficiency of 2.1\%, an open-circuit voltage of 223 mV and a current density of 16 mA/cm(2) are presented. (C) 2014 Elsevier B.V. All rights reserved. [less ▲]

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See detailDetection of a MoSe2 secondary phase layer in CZTSe by spectroscopic ellipsometry
Demircio glu, Ozden; Mousel, Marina UL; Redinger, Alex UL et al

in JOURNAL OF APPLIED PHYSICS (2015), 118

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See detailDiffuse Electroreflectance of thin-film solar cells: Suppression of interference-related lineshape distortions
Krämmer, Christoph; Huber, Christian; Redinger, Alex UL et al

in Applied Physics Letters (2015), 107

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See detailDetection of Cu2Zn5SnSe8 and Cu2Zn6SnSe9 phases in co-evaporated Cu2ZnSnSe4 thin-films
Schwarz, Torsten; Marques, Miguel A.L.; Botti, Silvana et al

in Applied Physics Letters (2015), 107

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See detailAtom probe tomography study of internal interfaces in Cu2ZnSnSe4 thin-films
Schwarz, T.; Cojocaru-Mir edin, O.; Choi, P. et al

in Journal of Applied Physics (2015), 118

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See detailMultiple phases of Cu2ZnSnSe4 detected by room temperature photoluminescence (vol 116, 073509, 2014)
Djemour, Rabie; Redinger, Alex UL; Mousel, Marina et al

in JOURNAL OF APPLIED PHYSICS (2015), 118(8),

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See detailThe band gap of Cu2ZnSnSe4: Effect of order-disorder
Rey, Germain UL; Redinger, Alex UL; Sendler, Jan UL et al

in Applied Physics Letters (2014), 105

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See detailLoss mechanisms in kesterite
Siebentritt, Susanne UL; Redinger, Alex UL

in wiley (Ed.) Copper Zinc Tin Sulphide-Based Thin Film Solar Cells (2014)

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See detailEpitaxial Cu2ZnSnSe4 thin films and devices
Redinger, Alex UL; Groiss, Heiko; Sendler, Jan UL et al

in Thin Solid Films (2014)

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See detailAssessment of crystal quality and unit cell orientation in epitaxial Cu2ZnSnSe4 layers using polarized Raman scattering
Krämmer, Christoph; Lang Mario; Redinger, Alex UL et al

in Optics Express (2014), 22

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See detailMultiple phases of Cu2ZnSnSe4 detected by room temperature photoluminescence
Djemour, Rabie UL; Redinger, Alex UL; Mousel, Marina UL et al

in Journal of Applied Physics (2014), 116

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See detailAssessment of crystal quality and unit cell orientation in epitaxial Cu2ZnSnSe4 layers using polarized Raman scattering
Kraemmer, Christoph; Lang, Mario; Redinger, Alex UL et al

in OPTICS EXPRESS (2014), 22(23), 28240-28246

We use polarization-resolved Raman spectroscopy to assess the crystal quality of epitaxial kesterite layers. It is demonstrated for the example of epitaxial Cu2ZnSnSe4 layers on GaAs(001) that ``standing ... [more ▼]

We use polarization-resolved Raman spectroscopy to assess the crystal quality of epitaxial kesterite layers. It is demonstrated for the example of epitaxial Cu2ZnSnSe4 layers on GaAs(001) that ``standing'' and ``lying'' kesterite unit cell orientations (c'-axis parallel / perpendicular to the growth direction) can be distinguished by the application of Raman tensor analysis. From the appearance of characteristic intensity oscillations when the sample is rotated one can distinguish polycrystalline and epitaxial layers. The method can be transferred to kesterite layers oriented in any crystal direction and can shed light on the growth of such layers in general. (C) 2014 Optical Society of America [less ▲]

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See detailCu2ZnSnSe4 thin film solar cells produced via co-evaporation and annealing including a SnSe2 capping layer
Redinger, Alex UL; Mousel, Marina; Djemour, Rabie et al

in PROGRESS IN PHOTOVOLTAICS (2014), 22(1), 51-57

Cu2ZnSnSe4 (CZTSe) thin film solar cells have been produced via co-evaporation followed by a high-temperature annealing. In order to reduce the decomposition of the CZTSe, a SnSe2 capping layer has been ... [more ▼]

Cu2ZnSnSe4 (CZTSe) thin film solar cells have been produced via co-evaporation followed by a high-temperature annealing. In order to reduce the decomposition of the CZTSe, a SnSe2 capping layer has been evaporated onto the absorber prior to the high-temperature treatment. This eliminates the Sn losses due to SnSe evaporation. A solar cell efficiency of 5.1 could be achieved with this method. Moreover, the device does not suffer from high series resistance, and the dominant recombination pathway is situated in the absorber bulk. Finally different illumination conditions (white light, red light, and yellow light) reveal a strong loss in fill factor if no carriers are generated in the CdS buffer layer. This effect, known as red-kink effect, has also been observed in the closely related Cu(In,Ga)Se-2 thin film solar cells. Copyright (c) 2013 John Wiley Sons, Ltd. [less ▲]

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