References of "Regesch, David 50002916"
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See detailDeliberate and Accidental Gas-Phase Alkali Doping of Chalcogenide Semiconductors: Cu(In,Ga)Se2
Colombara, Diego UL; Berner, Ulrich; Ciccioli, Andrea et al

in Scientific Reports (2017), 7

Alkali metal doping is essential to achieve highly efficient energy conversion in Cu(In,Ga)Se2 (CIGSe) solar cells. Doping is normally achieved through solid state reactions, but recent observations of ... [more ▼]

Alkali metal doping is essential to achieve highly efficient energy conversion in Cu(In,Ga)Se2 (CIGSe) solar cells. Doping is normally achieved through solid state reactions, but recent observations of gas phase alkali transport in the kesterite sulfide (Cu2ZnSnS4) system (re)open the way to a novel gas-phase doping strategy. However, the current understanding of gas-phase alkali transport is very limited. This work (i) shows that CIGSe device efficiency can be improved from 2% to 8% by gas-phase sodium incorporation alone, (ii) identifies the most likely routes for gas-phase alkali transport based on mass spectrometric studies, (iii) provides thermochemical computations to rationalize the observations and (iv) critically discusses the subject literature with the aim to better understand the chemical basis of the phenomenon. These results suggest that accidental alkali metal doping occurs all the time, that a controlled vapor pressure of alkali metal could be applied during growth to dope the semiconductor, and that it may have to be accounted for during the currently used solid state doping routes. It is concluded that alkali gas-phase transport occurs through a plurality of routes and cannot be attributed to one single source. [less ▲]

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See detailWhat is the band gap of kesterite?
Siebentritt, Susanne UL; Rey, Germain UL; Finger, Ashley UL et al

in Solar Energy Materials & Solar Cells (2015)

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See detailPrediction of photovoltaic p-n device short circuit current by photoelectrochemical analysis of p-type CIGSe films
Colombara, Diego UL; Crossay, Alexandre UL; Regesch, David UL et al

in Electrochemistry Communications (2014), 48

The quality control of individual semiconductor thin films during fabrication of multiple layers is important for industry and academia. The ultimate aim of this research is to predict the efficiency of p ... [more ▼]

The quality control of individual semiconductor thin films during fabrication of multiple layers is important for industry and academia. The ultimate aim of this research is to predict the efficiency of p-–n junction solar cells by photoelectrochemical analysis of the bare p-type semiconductor. A linear correlation between the photocurrent measured electrochemically on Cu(In,Ga)Se2 absorber layers through a Eu3+ electrolyte junction and short circuit current and efficiency of the corresponding solid state devices is found. However, the correlation is complicated by pronounced recombination at the semiconductor/electrolyte interface, while the solid state interface behaves more ideally. [less ▲]

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See detailPhotoluminescence and solar cell studies of chalcopyrites - comparison of Cu-rich vs. Cu-poor and polycrystalline vs. epitaxial material
Regesch, David UL

Doctoral thesis (2014)

The quasi-Fermi level splitting (qFls) in a solar cell absorber limits the maximum achievable open circuit voltage of the final device. A calibrated photoluminescence set-up allows the determination of ... [more ▼]

The quasi-Fermi level splitting (qFls) in a solar cell absorber limits the maximum achievable open circuit voltage of the final device. A calibrated photoluminescence set-up allows the determination of the qFls at room temperature under conditions equivalent to the illumination from the sun. In this work the qFls is used as an indicator for the quality of epitaxial and polycrystalline thin CuInSe2 films with different compositions. It is shown, that the epitaxial material exhibits improved optoelectronic quality noticeable in the higher qFls (50-100meV) when compared to the polycrystalline counterpart. Furthermore, a dependency on the Cu/In ratio is noticed: In Cu poor material (Cu/In<1) the qFls increases with an increasing Cu concentration and levels off for the absorbers grown under Cu-rich conditions (Cu/In>1). The difference between absorbers grown under Cu-poor and Cu-rich conditions is found to be in the order of 150meV. Additionally, the compositional dependence of the Urbach energy and of the band gap energy has been evaluated from the PL spectra at room temperature. Slightly higher bandgaps and lower Urbach energies have been found for the Cu rich material compared to the Cu poor absorbers. The time dependent change of the qFls of bare CuInSe2 absorbers exposed to air is presented and shows for Cu-poor absorbers a pronounced and for Cu-rich material a slower degradation. It is shown, that a chemical etching in potassium cyanide refreshes the degraded material to an extent comparable to freshly grown samples, and that the deposition of a CdS buffer layer passivates the surface. Epitaxial Cu(In,Ga)Se2 is grown by means of metal organic vapour phase epitaxy and used to produce epitaxial solar cells. A maximum power conversion efficiency of 6.7% has been achieved. All solar cells suffer from dominant interface recombination processes which limit the device performance. The critical interface is between the absorber layer and the CdS buffer and related to the high gallium content. [less ▲]

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See detailCuInSe2 semiconductor formation by laser annealing
Meadows, Helen UL; Regesch, David UL; Thevenin, Maxime UL et al

in Thin Solid Films (2014)

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See detailDirect Evaluation of Defect Distributions From Admittance Spectroscopy
Weiss, Thomas Paul UL; Redinger, Alex UL; Regesch, David UL et al

in IEEE JOURNAL OF PHOTOVOLTAICS (2014), 4

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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 detailSingle Second Laser Annealed CuInSe2 Semiconductors from Electrodeposited Precursors as Absorber Layers for Solar Cells
Meadows, Helen UL; Bathia, Ashish; Depredurand, Valérie UL et al

in Journal of Physical Chemistry C (2014), 118 (3)

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See detailComposition dependent characterization of copper indium diselenide thin film solar cells synthesized from electrodeposited binary selenide precursor stacks
Fischer, Johannes; Larsen, Jes K. UL; Guillot, Jerôme et al

in Solar Energy Materials & Solar Cells (2014), 126

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See detailWhy do we make Cu(In,Ga)Se2 solar cells non-stoichiometric?
Siebentritt, Susanne UL; Gütay, Levent UL; Regesch, David UL et al

in Solar Energy Materials & Solar Cells (2013)

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See detailFeedback mechanism for the stability of the band gap of CuInSe2
Gutay, Levent UL; Regesch, David UL; Larsen, Jes K. UL et al

in Physical Review (2012), 86

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See detailDegradation and passivation of CuInSe2
Regesch, David UL; Gütay, Levent UL; Larsen, Jes K. UL et al

in Applied Physics Letters (2012), 101

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See detailInfluence of copper excess on the absorber quality of CulnSe2
Gütay, Levent UL; Regesch, David UL; Larsen, Jes K. UL et al

in Applied Physics Letters (2011), 99(151912), 1519121-15191123

Detailed reference viewed: 81 (17 UL)