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Characterization of Sputtered CdTe Thin Films with Electron Backscatter Diffraction and Correlation with Device Performance

Published online by Cambridge University Press:  16 June 2015

Matthew M. Nowell ,
Michael A. Scarpulla ,
Naba R. Paudel ,
Kristopher A. Wieland ,
Alvin D. Compaan  and
Xiangxin Liu
Matthew M. Nowell
Affiliation:
EDAX-TSL, 392 East 12300 South Suite H, Draper, UT 84020, USA
Michael A. Scarpulla
Affiliation:
Departments of Materials Science and Engineering and Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112, USA
Naba R. Paudel*
Affiliation:
Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA
Kristopher A. Wieland
Affiliation:
Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA
Alvin D. Compaan
Affiliation:
Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA
Xiangxin Liu
Affiliation:
Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA
*
*Corresponding author.naba.paudel@utoledo.edu
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Abstract

The performance of polycrystalline CdTe photovoltaic thin films is expected to depend on the grain boundary density and corresponding grain size of the film microstructure. However, the electrical performance of grain boundaries within these films is not well understood, and can be beneficial, harmful, or neutral in terms of film performance. Electron backscatter diffraction has been used to characterize the grain size, grain boundary structure, and crystallographic texture of sputtered CdTe at varying deposition pressures before and after CdCl2 treatment in order to correlate performance with microstructure. Weak fiber textures were observed in the as-deposited films, with (111) textures present at lower deposition pressures and (110) textures observed at higher deposition pressures. The CdCl2-treated samples exhibited significant grain recrystallization with a high fraction of twin boundaries. Good correlation of solar cell efficiency was observed with twin-corrected grain size while poor correlation was found if the twin boundaries were considered as grain boundaries in the grain size determination. This implies that the twin boundaries are neutral with respect to recombination and carrier transport.

Keywords

CdTesputteringEBSDthin film
Type
Materials Applications and Techniques
Information
Microscopy and Microanalysis , Volume 21 , Issue 4 , August 2015 , pp. 927 - 935
Copyright
© Microscopy Society of America 2015 

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Footnotes

†

Current address: Corning Incorporated, One Riverfront Plaza, Corning, NY 14831 USA

‡

Current address: Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, P.R. China

References

Abou-Ras, D., Koch, C.T., Küstner, V., Van Aken, P.A., Jahn, U., Contreras, M.A., Caballero, R., Kaufmann, C.A., Scheer, R., Unold, T. & Schock, H.W. (2009). Grain-boundary types in chalcopyrite-type thin films and their correlations with film texture and electrical properties. Thin Solid Films 517, 2545–2549.Google Scholar
Abou-Ras, D. & Pantleon, K. (2007). The impact of twinning on the local texture of chalcopyrite-type thin films. Phys Stat Sol (RRL) 1, 187–189.Google Scholar
Abramoff, M.D., Magalhaes, P.J. & Ram, S.J. (2004). Image processing with imageJ. Biophoto Inter 11, 36–43.Google Scholar
Bhatia, A., Dale, P.J., Nowell, M.M. & Scarpulla, M.A. (2010). Pulsed laser processing of electrodeposited CuInSe2 photovoltaic absorber thin films. Proc Mater Res Soc 1268, 103.Google Scholar
Brewer, L.N., Field, D.P. & Merriman, C.C. (2009). Mapping and assessing plastic deformation using EBSD. In Electron Backscatter Diffraction in Materials Science, 2nd ed. Schwartz, A.J., Kumar, M., Field, D.P. & Adams, B.L. (Eds.), pp. 251–262. Springer.Google Scholar
Bunge, H.J. (1993). Texture Analysis in Materials Science: Mathematical Methods. Gottingen, Germany: Cuvillier Verlag.Google Scholar
Compaan, A.D. (2006). Photovoltaics: Clean power for the 21st century. Sol Energy Mater Sol Cells 90, 2170–2180.Google Scholar
Consonni, V., Feuillet, G. & Gergaud, P. (2008). Plasticity induced texture development in thick polycrystalline CdTe: Experiments and modeling. J Appl Phys 103, 063529.Google Scholar
Eisenbarth, T., Unold, T., Caballero, R., Kaufman, C.A., Abou-Ras, D. & Schock, H.W. (2009). Origin of defects in CuIn1-xGaxSe2 solar cell with varied Ga content. Thin Solid Films 517, 2244–2247.CrossRefGoogle Scholar
Field, D.P. (1997). Recent advances in the application of orientation imaging. Ultramicroscopy 67, 1–9.Google Scholar
Field, D.P., Sanchez, J.E., Park, N.J. & Besser, P.R. (2005). Texture evolution in thin Cu films and lines, materials science forum. In Textures of Materials—ICOTOM 14, Van Houtte, P. & Kestens L. (Eds.), Vols 495--497, pp. 1323–1332. Leuven, Belgium: Trans Tech Publications.Google Scholar
Fraas, L.M. (1978). Basic grain‐boundary effects in polycrystalline heterostructure solar cells. J Appl Phys 49, 871.Google Scholar
Gupta, A. & Compaan, A.D. (2004). All-sputtered 14% CdS/CdTe thin-film solar cell with ZnO: Al transparent conducting oxide. Appl Phys Lett 85, 684–686.Google Scholar
Hlaing, O.O.W.M., Johnson, J.L., Bhatia, A., Lund, E.A., Nowell, M.M. & Scarpulla, M.A. (2011). Grain size and texture of Cu2ZnSnS4 thin films synthesized by co-sputtering binary sulfides and annealing: Effects of processing conditions and sodium. J Electron Mater 40, 2214–2221.Google Scholar
Li, C., Wu, Y., Poplawsky, J., Pennycook, R.J., Paudel, N.R., Yin, W., Haigh, S.J., Oxley, M.P., Lupini, A.R., Al-Jassm, M., Pennycook, S.J. & Yan, Y. (2014). Grain-boundary-enhanced carrier collection in CdTe solar cells. Phys Rev Let 112, 156103.Google Scholar
Major, J.D., Proskuryakov, Y.Y., Durose, K., Zoppi, G. & Forbes, I. (2010). Control of grain size in sublimation-grown CdTe, and the improvement in performance of devices with systematically increased grain size. Sol Energy Mater Sol Cells 94, 1107–1112.Google Scholar
Manivannan, V., Enzenroth, R.A., Barth, K.L., Kohli, S., Mccurdy, P.R. & Sampath, W.S. (2008). Microstructural features of CdTe PV thin film devices. Thin Solid Films 516, 1209–1213.CrossRefGoogle Scholar
Matteson, T.L., Schwarz, S.W., Houge, E.C., Kempshall, B.W. & Giannuzzi, L.A. (2002). Electron backscattering diffraction investigation of focused ion beam surfaces. J Electron Mater 31, 33–39.Google Scholar
Michael, J.R. & Giannuzzi, L.A. (2007). Improved EBSD sample preparation via low energy Ga+ FIB ion milling. Microsc Microanal 13, 926–927.Google Scholar
Moutinho, H.R., Al-Jassim, M.M., Levi, D.H., Dippo, P.C. & Kazmerski, L.L. (1998). Papers from the 44 th National Symposium of the AVS . San Jose, CA, USA: AVS. 1251pp.Google Scholar
Moutinho, H.R., Dhere, R.G., Romero, M.J., Jiang, C.S., To, B. & Al-Jassim, M.M. (2008). Electron backscatter diffraction of CdTe thin films: Effects of CdCl2 treatment. J Vac Sci Tech A 26, 1068–1073.Google Scholar
Nalwa, H.G. (2002). Handbook of Thin Film Materials: Semiconductor and Superconductor Thin Films. San Diego, CA: Academic Press.Google Scholar
Nowell, M.M. (2002). Ion beam preparation of passivated copper integrated circuit structures for electron backscatter diffraction/orientation imaging microscopy analysis. J Electron Mater 31, 23–32.Google Scholar
Nowell, M.M. & Wright, S.I. (2005). Orientation effects on indexing of electron backscatter diffraction patterns. Ultramicroscopy 103, 41–58.Google Scholar
Park, N.-J. & Field, D.P. (2006). Predicting thickness dependent twin boundary formation in sputtered Cu films. Scripta Mater 54, 999–1003.Google Scholar
Park, N.-J., Field, D.P., Nowell, M.M. & Besser, P.R. (2005). Effect of film thickness on the evolution of annealing texture in sputtered copper films. J Electron Mater 34, 1500–1508.Google Scholar
Plotnikov, V.V., Vasko, A.C., Compaan, A.D., Liu, X., Wieland, K.A., Zeller, R.M., Li, J. & Collins, R.W. (2009). Magnetron sputtering for II-VI solar cells: Thinning the CdTe. Proc Mater Res Soc 1165, M09.Google Scholar
Randle, V. (2010). Grain boundary engineering: An overview after 25 years. Mater Sci Tech 26, 253–261.Google Scholar
Romeo, A., Batzner, D.L., Zogg, H. & Tiwari, A.N. (2000). Recrystallization in CdTe/CdS. Thin Solid Films 361–362, 420–425.CrossRefGoogle Scholar
Schwarzer, R.A., Field, D.P., Adams, B.L., Kumar, M. & Schwartz, A.J. (2009). Present state of electron backscatter diffraction and prospective developments. In Electron Backscatter Diffraction in Materials Science, 2nd ed. Schwartz, A.J., Kumar, M., Field, D.P. & Adams B.L. (Eds.), pp. 1–20. Springer.Google Scholar
Shao, M., Fischer, A., Grecu, D., Jayamaha, U., Bykov, E., Contreras-Puente, G., Bohn, R.G. & Compaan, A.D. (1996). Radio-frequency-magnetron-sputtered CdS/CdTe solar cells on soda-lime glass. Appl Phys Lett 69, 3045–3048.Google Scholar
Smith, S., Zhang, P., Gessert, T. & Mascarenhas, A. (2004). Near-field optical beam-induced currents in CdTe/CdS solar cells: Direct measurement of enhanced photoresponse at grain boundaries. Appl Phys Lett 85, 3854.Google Scholar
Thompson, C.V. & Carel, R. (1995). Texture development in polycrystalline thin films. Mater Sci Eng B 32, 211–219.Google Scholar
Thompson, C.V. & Carel, R. (1996). Stress and grain growth in thin films. J Mech Phys Solids 44, 657–673.Google Scholar
Visoly-Fisher, I., Cohen, S.R. & Cahen, D. (2003). Direct evidence for grain boundary depletion in polycrystalline CdTe from nanoscale-resolved measurement. Appl Phys Lett 82, 556–558.Google Scholar
Visoly-Fisher, I., Cohen, S.R., Gartsman, K., Ruzin, A. & Cahen, D. (2006). Understanding the beneficial role of grain boundaries in polycrystalline solar cells from single grain boundary scanning probe microscopy. Adv Funct Mater 16, 649–660.Google Scholar
Visoly-Fisher, I., Cohen, S.R., Ruzin, A. & Cahen, D. (2004). How polycrystalline devices can outperform single-crystal ones: Thin film CdTe/CdS solar cells. Adv Mater 16, 879–883.Google Scholar
Wright, S.I. (2002). Investigation of coincident site lattice boundary criteria in Cu thin films. J Electron Mater 31, 50–54.CrossRefGoogle Scholar
Wright, S.I., Field, D.P. & Dingley, D.J. (2000). Advanced software capabilities for automated EBSD. In Electron Backscatter Diffraction in Materials Science, Schwartz, A.J., Kumar, M. & Adams B.L. (Eds.), pp. 141–152. New York, NY: Kluwer Academic/Plenum Publishers.Google Scholar
Wright, S.I. & Larsen, R.J. (2002). Extracting twins from orientation imaging microscopy scan data. J Microsc 205, 245–252.Google Scholar
Wright, S.I. & Nowell, M.M. (2006). EBSD image quality mapping. Microsc Microanal 12, 72–84.Google Scholar
Wright, S.I., Nowell, M.M. & Bingert, J.F. (2007). A comparison of textures measured using X-ray and electron backscatter diffraction. Metall Mater Trans A 38, 1845–1855.Google Scholar
Wright, S.I., Nowell, M.M. & Field, D.P. (2011). A review of strain analysis using EBSD. Microsc Microanal 17, 316–329.Google Scholar
Yan, Y., Al-Jassim, M.M., Jones, K., Wei, S.-H. & Zhang, S.B. (2000). Observation and first-principles calculations of buried wurtzite phases in zinc-blende CdTe thin films. Appl Phys Lett 77, 1461–1463.Google Scholar
Yan, Y., Jones, K.M., Jiang, C.S., Wu, X.Z., Noufi, R. & Al-Jassim, M.M. (2007). Understanding the defect physics in polycrystalline photovoltaic materials. Physica B 401–402, 25–32.Google Scholar
Zaefferer, S., Wright, S.I. & Raabe, D. (2008). Three dimensional orientation microscopy in a focused ion beam-scanning electron microscope: A new dimension of microstructure characterization. Metall Mater Trans A 39, 374–389.Google Scholar
Zoppi, G., Durose, K., Irvine, S.J.C. & Barrioz, V. (2006). Grain and crystal texture properties of absorber layers in MOCVD-grown CdTe/CdS solar cells. Semicond Sci Technol 21, 763–770.Google Scholar
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