Search Results - "Warta, W."

Photoluminescence imaging of silicon wafers by 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…”
Get full text

Prediction of silicon PV module temperature for hot spots and worst case partial shading situations using spatially resolved lock-in thermography by Geisemeyer, I., Fertig, F., Warta, W., Rein, S., Schubert, M.C.

“…In this paper we propose a method to predict hot spot temperatures in crystalline silicon photovoltaic modules operating under critical shading conditions…”
Get full text

Short-circuit current density mapping for solar cells by Padilla, M., Michl, B., Thaidigsmann, B., Warta, W., Schubert, M.C.

“…A map of local short-circuit current density (JSC) of a solar cell at standard irradiance spectra is a desirable source of information for current-loss…”
Get full text

Minority carrier lifetime imaging of silicon wafers calibrated by quasi-steady-state photoluminescence by Giesecke, J.A., Schubert, M.C., Michl, B., Schindler, F., Warta, W.

“…Reliable process control or predictions of solar cell efficiencies from minority carrier lifetimes on silicon wafers require precise lifetime measurements. For…”
Get full text

Understanding carrier lifetime measurements at nonuniform recombination by Giesecke, J. A., Warta, W.

“…Effective lifetimes as measured via dynamic vs. steady-state techniques may drastically diverge in the presence of a highly nonuniform spatial distribution of…”
Get full text

Efficiency limiting bulk recombination in multicrystalline silicon solar cells by Michl, B., Rüdiger, M., Giesecke, J.A., Hermle, M., Warta, W., Schubert, M.C.

“…In this paper we measure, spatially resolved, the efficiency potential of multicrystalline material. The excess carrier lifetime in the bulk affects the…”
Get full text

Characterization and optimization of indium tin oxide films for heterojunction solar cells by Balestrieri, M., Pysch, D., Becker, J.-P., Hermle, M., Warta, W., Glunz, S.W.

“…Well suited and reliable values of the optical and electrical properties of thin indium tin oxide (ITO) films are needed in order to choose the optimal…”
Get full text

Luminescence imaging for the detection of shunts on silicon solar cells by Kasemann, M., Grote, D., Walter, B., Kwapil, W., Trupke, T., Augarten, Y., Bardos, R.A., Pink, E., Abbott, M.D., Warta, W.

“…Luminescence imaging is a non‐destructive, fast, and versatile imaging method for spatially resolved solar cell and material characterization. In this paper,…”
Get full text

Estimation of angle-dependent mode coupling and attenuation in step-index plastic optical fibers from impulse responses by Mundus, M, Hohl-Ebinger, J, Warta, W

“…We report on a method for estimation of angle-dependent mode coupling and attenuation in step-index plastic optical fibers (SI-POFs) from the shapes of impulse…”
Get full text

Minority carrier lifetime of silicon solar cells from quasi-steady-state photoluminescence by GIESECKE, J. A, MICHL, B, SCHINDLER, F, SCHUBERT, M. C, WARTA, W

“…Minority carrier lifetime is the most crucial material parameter for the performance of a silicon solar cell. While numerous methods exist to determine carrier…”
Get full text

Self-sufficient minority carrier lifetime in silicon from quasi-steady-state photoluminescence by Giesecke, J. A., Schubert, M. C., Warta, W.

“…Quasi‐steady‐state photoluminescence is a versatile technique to determine carrier lifetime in silicon. A recent approach extracts carrier lifetime without a…”
Get full text

Spectral response measurements of monolithic GaInP/Ga(In)As/Ge triple-junction solar cells: Measurement artifacts and their explanation by Meusel, M., Baur, C., Létay, 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…”
Get full text

Advanced defect and impurity diagnostics in silicon based on carrier lifetime measurements by 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…”
Get full text

Interstitial oxygen imaging from thermal donor growth—A fast photoluminescence based method by Niewelt, T., Lim, S., Holtkamp, J., Schön, J., Warta, W., Macdonald, D., Schubert, M.C.

“…We present a fast method to create interstitial oxygen concentration maps from resistivity calibrated photoluminescence images prior to and after a heat…”
Get full text

Surface recombination parameters of interdigitated-back-contact silicon solar cells obtained by modeling luminescence images by Padilla, M., Höffler, H., Reichel, C., Chu, H., Greulich, J., Rein, S., Warta, W., Hermle, M., Schubert, M.C.

“…Current losses at surfaces play a crucial role in the optimization of high-efficiency silicon solar cells. We present a new approach to characterize the…”
Get full text

Spectral mismatch correction and spectrometric characterization of monolithic III-V multi-junction solar cells by Meusel, M., Adelhelm, R., Dimroth, F., Bett, A.W., Warta, W.

“…III–V monolithic multi‐junction (MJ) solar cells reach efficiencies exceeding 30% (AM 1.5 global) and have applications in space and in terrestrial…”
Get full text

Impact of metal silicide precipitate dissolution during rapid thermal processing of multicrystalline silicon solar cells by Buonassisi, T., Istratov, A. A., Peters, S., Ballif, C., Isenberg, J., Riepe, S., Warta, W., Schindler, R., Willeke, G., Cai, Z., Lai, B., Weber, E. R.

“…Synchrotron-based analytical x-ray microprobe techniques were employed to study the dissolution of iron, copper, and nickel silicide precipitates at structural…”
Get full text

Iron related solar cell instability: Imaging analysis and impact on cell performance by Schubert, M.C., Padilla, M., Michl, B., Mundt, L., Giesecke, J., Hohl-Ebinger, J., Benick, J., Warta, W., Tajima, M., Ogura, A.

“…Iron is an omnipresent and efficiency-limiting impurity in p-type silicon solar cells. A very useful technique to detect the interstitial iron concentration in…”
Get full text

Separation of local bulk and surface recombination in crystalline silicon from luminescence reabsorption by Giesecke, J. A., Kasemann, M., Schubert, M. C., Würfel, P., Warta, W.

“…Spontaneous photoemission of crystalline silicon provides information on excess charge carrier density and thereby on electronic properties such as charge…”
Get full text

Characterization of monolithic III–V multi-junction solar cells—challenges and application by 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…”
Get full text