W. Warta

Publication List Details

Period

1988 - 2008

Number

136

Co-Authors

Emissivity-corrected power loss calibration for lock-in thermography measurements on silicon solar cells (2008)

Kasemann, M., Walter, B., Meinhardt, C., Ebser, J., Kwapil, W., Warta, W.

This paper describes power loss calibration procedures with implemented emissivity correction. The determination of our emissivity correction matrix does neither rely on blackbody reference...

Electronic properties of titanium in boron-doped silicon analyzed by temperature-dependent photoluminescence and injection-dependent photoconductance lifetime spectroscopy (2008)

Roth, T., Rüdiger, M., Warta, W., Glunz, S.W.

Temperature-dependent lifetime spectroscopy allows for the determination of defect parameters (like ratio of the carrier capture cross sections and energy level) of pointlike defects in silicon. This...

Origin of trapping in multicrystalline silicon (2008)

Gundel, P., Schubert, M.C., Warta, W.

Defect sites in silicon, which temporarily capture excess charge carriers (traps), are a promising source of information on defect structures relevant for photovoltaic application of the material. In...

Spatially resolved modeling of the combined effect of dislocations and grain boundaries on minority carrier lifetime in multicrystalline silicon (2007)

Stokkan, G., Riepe, S., Lohne, O., Warta, W.

A model for the combined effect of dislocations and grain boundaries on minority carrier lifetime has been developed. Lifetime varies with dislocation density, grain boundary misorientation, and the...

Solar cell efficiency tables (version 29) (2007)

Green, M.A., Emery, K., King, D.L., Hishikawa, Y., Warta, W.

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables...

Diffusion lengths of silicon solar cells from luminescence images (2007)

Würfel, P., Trupke, T., Puzzer, T., Schäffer, E., Warta, W., Glunz, S.W.

A method for spatially resolved measurement of the minority carrier diffusion length in silicon wafers and in silicon solar cells is introduced. The method, which is based on measuring the ratio of...

Solar cell efficiency tables (version 30) (2007)

Green, M.A., Emery, K., Hisikawa, Y., Warta, W.

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables...

Verfahren und Vorrichtung zur Inaktivierung von Trapping-Effekten in dotierten Halbleitern (2006)

Schubert, M., Rein, S., Isenberg, J., Warta, W., Glunz, S.W.

WO 2006092321 A1 UPAB: 20061103 NOVELTY - The method involves injecting subband photons from e.g. a laser source into a semiconductor (6), preferably heated to 60degreesC in order to empty the trap...

Advanced defect and impurity diagnostics in silicon based on carrier lifetime measurements (2006)

Warta, W.

An overview is given on recent developments at Fraunhofer ISE in the field of diagnostic techniques based on carrier lifetime measurements. The status of the different lifetime spectroscopy methods...

Characterization of monolithic III-V multi-junction solar cells - challenges and application (2006)

Meusel, M., Baur, C., Siefer, G., Dimroth, F., Bett, A.W., Warta, W.

The characterization of monolithic III-V multi-junction solar cells is still a challenging task. In this paper we show that quantum efficiency measurements have to be performed under optimized light-...

Comparison of luminescence imaging and illuminated lock-in thermography on silicon solar cells (2006)

Kasemann, M., Schubert, M.C., The, M., Köber, M., Hermle, M., Warta, W.

Spatially resolved electroluminescence (EL) and photoluminescence (PL) images of solar cells are compared to spatially resolved power loss images obtained by illuminated lock-in thermography (ILIT)....

Determination of spatially resolved trapping parameters in silicon with injection dependent carrier density imaging (2006)

Schubert, M.C., Riepe, S., Bermejo, S., Warta, W.

We present spatially resolved and injection dependent excess carrier lifetime measurements on silicon. At low level injection conditions an anomalous increase often interferes in such measurements....

Effect of dislocations on open circuit voltage in crystalline silicon solar cells (2006)

Kieliba, T., Riepe, S., Warta, W.

The dislocation dependence of open circuit voltage is studied based on Donolato's model for the effect of dislocations on minority carrier effective diffusion length [J. Appl. Phys. 84, 2656...

Effect of dislocations on minority carrier diffusion length in practical silicon solar cells (2006)

Kieliba, T., Riepe, S., Warta, W.

In 1998, Donolato presented an analytical model describing the effect of dislocation density on minority carrier effective diffusion length [J. Appl. Phys. 84, 2656 (1998)]. While this analysis was...

Photoluminescence imaging of silicon wafers (2006)

Trupke, T., Bardos, R.A., Schubert, M.C., Warta, W.

Photoluminescence imaging is demonstrated to be an extremely fast spatially resolved characterization technique for large silicon wafers. The spatial variation of the effective minority carrier...

Solar cell efficiency tables (version 28): Short communication (2006)

Green, M.A., Emery, K., King, D.L., Hishikawa, Y., Warta, W.

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables...

Solar cell efficiency tables (version 27): Short communication (2006)

Green, M.A., Emery, K., King, D.L., Hisikawa, Y., Warta, W.

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables...

Short communication: Solar cell efficiency tables (version 25) (2005)

Green, M.A., Emery, K., King, D.L., Igari, S., Warta, W.

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables...

Synchrotron-based investigations of the nature and impact of iron contamination in multicrystalline silicon solar cells (2005)

Buonassisi, T., Istratov, A.A., Heuer, M., Marcus, M.A., Jonczyk, R., Isenberg, J., ...

Synchrotron-based microprobe techniques were used to obtain systematic information about the size distribution, spatial distribution, shape, electrical activity, chemical states, and origins of...

Solar cell efficiency tables (version 26) (2005)

Green, M.A., Emery, K., King, D.L., Igari, S., Warta, W.

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables...

Solar cell efficiency tables (version 26) (2005)

Green, M.A., Emery, K., King, D.L., Igari, S., Warta, W.

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables...

Solar cell efficiency tables (version 25) (2005)

Green, M.A., Emery, K., King, D.L., Igari, S., Warta, W.

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables...

Carrier density imaging as a tool for characterising the electrical activity of defects in pre-processed multicrystalline silicon (2004)

Riepe, S., Stokkan, G., Kieliba, T., Warta, W.

In this work we present Carrier Density Imaging as a tool for the assessment of the recombitation activity of defects in multicrystal line silicon. A model for the excess minority carrier density in...

Verfahren und Anordnung zur strahlungsinduzierten Bestimmung der lokalen Verteilung von Verluststroemen bzw. Verlustleistung in Halbleiterbauelementen (2004)

Isenberg, J., Warta, W., Riepe, S.

DE 10240060 A UPAB: 20040514 NOVELTY - Method for determination of local distributions of current or power losses in semiconductor elements by measurement and evaluation of local temporal temperature...

Free carrier absorption in heavily doped silicon layers (2004)

Isenberg, J., Warta, W.

The standard parametrization of free carrier absorption in silicon predicting a linear dependence of the absorption on carrier concentration is revised, finding that due to several simplifications,...

Fast, contactless and spatially resolved measurement of sheet resistance by an infrared method (2004)

Isenberg, J., Biro, D., Warta, W.

The principle of free carrier absorption in combination with a CCD camera sensitive in the infrared is used to establish a measurement method for the emitter sheet resistance of silicon solar cells....

Spatially resolved evaluation of power losses in industrial solar cells by illuminated lock-in thermography (2004)

Isenberg, J., Warta, W.

The principles of a recently introduced measurement technique for power losses in solar cells, illuminated lock-in thermography (ILT), are reviewed. The main advantage of ILT over dark lock-in...

Realistic evaluation of power losses in solar cells by using thermographic methods (2004)

Isenberg, J., Warta, W.

The spatially resolved evaluation of power losses in solar cells is a key issue in identifying technological and material quality problems and realistically judging their influence on solar cell...

Imaging method for laterally resolved measurement of minority carrier densities and lifetimes: measurement principle and first applications (2003)

Isenberg, J., Riepe, S., Glunz, S.W., Warta, W.

Carrier density imaging, a further development of the infrared lifetime mapping technique [Bail et al., Proceedings 28th IEEE-PVSC (2000)], is presented as an extremely fast, spatially resolved...

Averaging of laterally inhomogeneous lifetimes for one-dimensional modeling of solar cells (2003)

Isenberg, J., Dicker, J., Warta, W.

This paper investigates the influence of laterally inhomogeneous cell parameters on solar cell efficiency. A universal procedure is proposed which allows the reduction of a frequency distribution of...

Spatially resolved lifetime imaging of silicon wafers by measurement of infrared emission (2003)

Schubert, M.C., Isenberg, J., Warta, W.

The measurement of infrared absorption of excess carriers is a successful technique by which images of the excess free carrier density and recombination lifetime in silicon can be generated. Carrier...

Spectral response measurements of monolithic GaInP/Ga(In)As/Ge triple-junction solar cells: Measurement artifacts and their explanation (2003)

Meusel, M., Baur, C., Letay, G., Bett, A.W., Warta, W., Fernandez, E.

Procedures for measuring the spectral response of multi-junction cells in general require variation of the bias spectrum and voltage biasing. It is shown that a refined procedure including...

Defect and impurity diagnostics and process monitoring (2002)

Warta, W.

The review focuses on four areas of defect and impurity diagnostics: (i) the determination of parasitic resistances, (ii) quantum efficiency analysis including light-beam-induced current measurement...