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Thalheim, Germany

Chowdhury A.,French National Center for Scientific Research | Schneider J.,CSG Solar AG | Schneider J.,Fraunhofer Center for Silicon Photovoltaics | Dore J.,CSG Solar AG | And 3 more authors.
Applied Physics A: Materials Science and Processing | Year: 2012

Thin film polycrystalline silicon films grown on glass substrate were irradiated with an infrared continuous wave laser for defects annealing and/or dopants activation. The samples were uniformly scanned using an attachment with the laser system. Substrate temperature, scan speed and laser power were varied to find suitable laser annealing conditions. The Raman spectroscopy and Suns-V ∞c analysis were carried out to qualify the films quality after laser annealing. A maximum enhancement of the open circuit voltage V ∞c of about 100 mV is obtained after laser annealing of as-grown polysilicon structures. A strong correlation was found between the full width half maximum of the Si crystalline peak and V ∞c. It is interpreted as due to defects annealing as well as to dopants activation in the absorbing silicon layer. The maximum V ∞c reached is 485 mV after laser treatment and plasma hydrogenation, thanks to defects passivation. © 2012 Springer-Verlag. Source

Straube H.,Max Planck Institute of Microstructure Physics | Straube H.,Sovello AG | Wagner J.-M.,Max Planck Institute of Microstructure Physics | Wagner J.-M.,University of Kiel | And 3 more authors.
Journal of Applied Physics | Year: 2011

We describe the measurement and modeling of lock-in thermograms for three differently processed crystalline silicon on glass thin film silicon solar modules. For the purpose of defect impact evaluation, a bias series of lock-in thermograms for a single cell in each module is measured. The resulting images around maximum power point bias show pronounced Peltier heat redistribution inside the cell, which needs to be taken into account for quantitative evaluation of the thermography results. This is done using a finite differences electronics simulation of the current flow inside the module and convolution of the heat distribution patterns with the thermal blurring. The procedure makes it possible to extract relevant cell performance parameters like the area diode dark saturation current and nonlinear edge shunting current densities as well as to evaluate the relative impact of these on the efficiency under simulated illumination. © 2011 American Institute of Physics. Source

Mchedlidze T.,TU Brandenburg | Schneider J.,CSG Solar AG | Arguirov T.,TU Brandenburg | Arguirov T.,Ihp Microelectronics | And 2 more authors.
Physica Status Solidi (C) Current Topics in Solid State Physics | Year: 2011

Thin film of amorphous Si deposited on glass substrate was crystallized at 600 °C using solid phase crystallization and further processed for PV application using Crystalline Silicon on Glass technology. The resulting film was polycrystalline and contained dislocations in large density. Photoluminescence (PL) and SunsVoc measurements were applied for characterization of the material properties. The intensity of radiative transitions related to dislocations (DRL) measured at room temperature supplied information about specificities of non-radiative recombination in the material and nicely correlated with open circuit voltage, measured using SunsVoc method. The PL measurements at room temperature showed a capability of fast and reliable prediction of PV performance of the film. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Lausch D.,Fraunhofer Center for Silicon Photovoltaics | Werner M.,Fraunhofer Center for Silicon Photovoltaics | Naumann V.,Fraunhofer Center for Silicon Photovoltaics | Schneider J.,CSG Solar AG | Hagendorf C.,Fraunhofer Center for Silicon Photovoltaics
Physica Status Solidi (C) Current Topics in Solid State Physics | Year: 2011

In this paper a method for studying p-n junctions is described. Different electron and ion beam charactersiation methods are introduced to determine the p-n-junction position using two different examples from Crystalline Silicon on Glass (CSG) thin film technology. In a first example lateral and cross section electron beam induced current (EBIC) measurements revealed that oxygen rich columnar growth at textured substrates disturbs strongly the p-n junction. In a second example diffusion from glass specimen is identified by TOF-SIMS to influencing the electrical and structural characteristics of the thin Si layer are responsible for the modified p-n junction. A model describing the formation of both defect structures is introduced. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Steffens S.,Helmholtz Center Berlin | Becker C.,Helmholtz Center Berlin | Zollondz J.-H.,CSG Solar AG | Chowdhury A.,LInstitut dElectronique du Solide et des Systemes | And 5 more authors.
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2013

A variety of defect healing methods was analyzed for optimization of polycrystalline silicon (poly-Si) thin-film solar cells on glass. The films were fabricated by solid phase crystallization of amorphous silicon deposited either by plasma enhanced chemical vapor deposition (PECVD) or by electron-beam evaporation (EBE). Three different rapid thermal processing (RTP) set-ups were compared: A conventional rapid thermal annealing oven, a dual wavelength laser annealing system and a movable two sided halogen lamp oven. The two latter processes utilize focused energy input for reducing the thermal load introduced into the glass substrates and thus lead to less deformation and impurity diffusion. Analysis of the structural and electrical properties of the poly-Si thin films was performed by Suns-VOC measurements and Raman spectroscopy. 1 cm2 cells were prepared for a selection of samples and characterized by I-V-measurements. The poly-Si material quality could be extremely enhanced, resulting in increase of the open circuit voltages from about 100 mV (EBE) and 170 mV (PECVD) in the untreated case up to 480 mV after processing. © 2012 Elsevier B.V. All rights reserved. Source

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