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Understanding the relationship between Cu2ZnSn(S,Se)4 material properties and device performance

Published online by Cambridge University Press:  28 November 2014

Talia Gershon*
Affiliation:
IBM TJ Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598
Tayfun Gokmen
Affiliation:
IBM TJ Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598
Oki Gunawan
Affiliation:
IBM TJ Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598
Richard Haight
Affiliation:
IBM TJ Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598
Supratik Guha
Affiliation:
IBM TJ Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598
Byungha Shin
Affiliation:
KAIST Department of Materials Science, Munji-ro 14, Yuseong-gu, Daejeon, South Korea
*
Address all correspondence to Talia Gershon at tsgersho@us.ibm.com
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Abstract

Cu2ZnSn(S,Se)4 (CZTSSe) photovoltaics (PV) have long been considered promising candidates for large-scale PV deployment due to the availability of constituent elements and steady improvements in device efficiency over time. The key limitation to high efficiency in this technology remains a deficit in the open-circuit voltage with respect to the band gap. The past decade has seen significant progress toward understanding how the various material properties such as bulk and surface composition, point defects (intrinsic and extrinsic), and grain boundaries all impact the optoelectronic properties of CZTSSe materials, and consequently device performance. This paper aims to summarize what is known about the CZTSSe bulk and surfaces, and how these material properties may be related to the Voc deficit.

Type
Prospective Articles
Copyright
Copyright © Materials Research Society 2014 

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References

1.Wang, W., Winkler, M.T., Gunawan, O., Gokmen, T., Todorov, T.K., Zhu, Y., and Mitzi, D.B.: Device characteristics of CZTSSe thin-film solar cells with 12.6% efficiency. Adv. Energy Mater. 4, (2014).Google Scholar
2.Lee, Y.S., Gershon, T., Gunawan, O., Todorov, T.K., Shin, B., Virgus, Y., and Guha, S.: Cu2ZnSnSe4 thin-film solar cells by thermal co-evaporation with 11.6% power conversion efficiency and improved minority carrier diffusion length. Adv. Energy Mater. (2014), DOI: 10.1002/aenm.201401372.Google Scholar
3.Kato, T., Hiroi, H., Sakai, N., Muraoka, S., and Sugimoto, H.: Characterization of front and back interfaces on Cu2ZnSnS4 thin-film solar cells. In Proc. of the 27th EU-PVSEC. Vol. 2236 (2012).Google Scholar
4.Mitzi, D.B., Gunawan, O., Todorov, T.K., and Barkhouse, D.A.R.: Prospects and performance limitations for Cu–Zn–Sn–S–Se photovoltaic technology. Philos. Trans. R. Soc. A 371, 20110432 (2013).Google Scholar
5.Kohara, N., Nishiwaki, S., Hashimoto, Y., Negami, T., and Wada, T.: Electrical properties of the Cu(In,Ga)Se2/MoSe2/Mo structure. Sol. Energy Mater. Sol. Cells 67, 209 (2001).Google Scholar
6.Abou-Ras, D., Kostorz, G., Bremaud, D., Kälin, M., Kurdesau, F., Tiwari, A., and Döbeli, M.: Formation and characterisation of MoSe2 for Cu(In,Ga)Se2 based solar cells. Thin Solid Films 480, 433 (2005).Google Scholar
7.Gunawan, O., Gokmen, T., and Mitzi, D.B.: Suns-VOC characteristics of high performance kesterite solar cells. J. Appl. Phys. 116, (2014).Google Scholar
8.Barkhouse, D.A.R., Haight, R., Sakai, N., Hiroi, H., Sugimoto, H., and Mitzi, D.B.: Cd-free buffer layer materials on Cu2ZnSn(SxSe1−x)4: Band alignments with ZnO, ZnS, and In2S3. Appl. Phys. Lett. 100, (2012).Google Scholar
9.Hiroi, H., Sakai, N., Muraoka, S., Katou, T., and Sugimoto, H.: Development of high efficiency Cu2ZnSnS4 submodule with Cd-free buffer layer. In Photovoltaic Specialists Conf. (PVSC), 2012 38th IEEE (IEEE, 2012), p. 001811.Google Scholar
10.Sakai, N., Hiroi, H., and Sugimoto, H.: Development of Cd-free buffer layer for Cu2ZnSnS4 thin-film solar cells. In Photovoltaic Specialists Conf. (PVSC), 2011 37th IEEE (IEEE, 2011), Seattle, WA, p. 003654.Google Scholar
11.Haight, R., Barkhouse, A., Gunawan, O., Shin, B., Copel, M., Hopstaken, M., and Mitzi, D.B.: Band alignment at the Cu2ZnSn(SxSe1−x)4/CdS interface. Appl. Phys. Lett. 98, (2011).Google Scholar
12.Nelson, J.: The Physics of Solar Cells (Imperial College Press, London, 2003).CrossRefGoogle Scholar
13.Kim, J., Hiroi, H., Todorov, T.K., Gunawan, O., Kuwahara, M., Gokmen, T., Nair, D., Hopstaken, M., Shin, B., Lee, Y.S., Wang, W., Sugimoto, H., and Mitzi, D.B.: High efficiency Cu2ZnSn(S,Se)4 solar cells by applying a double In2S3/CdS emitter. Adv. Mater. (2014). DOI: 10.1002/adma.201402373.Google Scholar
14.Chen, S., Walsh, A., Gong, X.-G., and Wei, S.-H.: Classification of lattice defects in the kesterite Cu2ZnSnS4 and Cu2ZnSnSe4 Earth-abundant solar cell absorbers. Adv. Mater. 25, 1522 (2013).Google Scholar
15.Katagiri, H., Jimbo, K., Tahara, M., Araki, H., and Oishi, K.: The influence of the composition ratio on CZTS-based thin film solar cells. In MRS Proc. (Cambridge University Press, vol. 1165, 2009), p. 1165Google Scholar
16.Vora, N., Blackburn, J., Repins, I., Beall, C., To, B., Pankow, J., Teeter, G., Young, M., and Noufi, R.: Phase identification and control of thin films deposited by co-evaporation of elemental Cu, Zn, Sn, and Se. J. Vac. Sci. Technol. A 30, (2012).Google Scholar
17.Chen, S., Yang, J.-H., Gong, X., Walsh, A., and Wei, S.-H.: Intrinsic point defects and complexes in the quaternary kesterite semiconductor Cu2ZnSnS4. Phys. Rev. B 81, 245204 (2010).Google Scholar
18.Chen, S., Wang, L.-W., Walsh, A., Gong, X., and Wei, S.-H.: Abundance of CuZn + SnZn and 2CuZn + SnZn defect clusters in kesterite solar cells. Appl. Phys. Lett. 101, 223901 (2012).Google Scholar
19.Nagaoka, A., Miyake, H., Taniyama, T., Kakimoto, K., and Yoshino, K.: Correlation between intrinsic defects and electrical properties in the high-quality Cu2ZnSnS4 single crystal. Appl. Phys. Lett. 103, 112107 (2013).Google Scholar
20.Mitzi, D.B., Gunawan, O., Todorov, T.K., Wang, K., and Guha, S.: The path towards a high-performance solution-processed kesterite solar cell. Sol. Energy Mater. Sol. Cells 95, 1421 (2011).Google Scholar
21.Gunawan, O., Virgus, Y., and Tai, K.F.: A parallel dipole line system. Appl. Phys. Lett. (2014, submitted).Google Scholar
22.Schorr, S., Hoebler, H.-J., and Tovar, M.: A neutron diffraction study of the stannite-kesterite solid solution series. Eur. J. Mineral. 19, 65 (2007).Google Scholar
23.Mendis, B.G., Shannon, M.D., Goodman, M.C., Major, J.D., Claridge, R., Halliday, D.P., and Durose, K.: Direct observation of Cu, Zn cation disorder in Cu2ZnSnS4 solar cell absorber material using aberration corrected scanning transmission electron microscopy. Prog. Photovolt. 22, 24 (2014).CrossRefGoogle Scholar
24.Schorr, S. and Tovar, M.: BENSC Experimental Report. (2006).Google Scholar
25.Shklovskii, B.I. and Efros, A.L.: Electronic Properties of Doped Semiconductors (Springer-Verlag, Berlin Heidelberg, 1984).CrossRefGoogle Scholar
26.Gokmen, T., Gunawan, O., Todorov, T.K., and Mitzi, D.B.: Band tailing and efficiency limitation in kesterite solar cells. Appl. Phys. Lett. 103, 103506 (2013).Google Scholar
27.Gershon, T., Shin, B., Bojarczuk, N., Gokmen, T., Lu, S., and Guha, S.: Photoluminescence characterization of a high-efficiency Cu2ZnSnS4 device. J. Appl. Phys. 114, 154905 (2013).Google Scholar
28.Romero, M.J., Du, H., Teeter, G., Yan, Y., and Al-Jassim, M.M.: Comparative study of the luminescence and intrinsic point defects in the kesterite Cu2ZnSnS4 and chalcopyrite Cu(In,Ga)Se2 thin films used in photovoltaic applications. Phys. Rev. B 84, 165324 (2011).Google Scholar
29.Gershon, T., Shin, B., Gokmen, T., Lu, S., Bojarczuk, N., and Guha, S.: Relationship between Cu2ZnSnS4 quasi donor–acceptor pair density and solar cell efficiency. Appl. Phys. Lett. 103, 193903 (2013).CrossRefGoogle Scholar
30.Miller, D.W., Warren, C.W., Gunawan, O., Gokmen, T., Mitzi, D.B., and Cohen, J.D.: Electronically active defects in the Cu2ZnSn(Se,S)4 alloys as revealed by transient photocapacitance spectroscopy. Appl. Phys. Lett. 101, 142106 (2012).Google Scholar
31.Gokmen, T., Gunawan, O., and Mitzi, D.B.: Semi-empirical device model for Cu2ZnSn(S,Se)4 solar cells. Appl. Phys. Lett. 105, 033903 (2014).Google Scholar
32.Washio, T., Nozaki, H., Fukano, T., Motohiro, T., Jimbo, K., and Katagiri, H.: Analysis of lattice site occupancy in kesterite structure of Cu2ZnSnS4 films using synchrotron radiation x-ray diffraction. J. Appl. Phys. 110, 074511 (2011).Google Scholar
33.Shockley, W. and Queisser, H.J.: Detailed balance limit of efficiency of p-n junction solar cells. J. Appl. Phys. 32, 510 (1961).Google Scholar
34.Rau, U. and Werner, J.: Radiative efficiency limits of solar cells with lateral band-gap fluctuations. Appl. Phys. Lett. 84, 3735 (2004).Google Scholar
35.Gunawan, O., Gokmen, T., Warren, C.W., Cohen, J.D., Todorov, T.K., Barkhouse, D.A.R., Bag, S., Tang, J., Shin, B., and Mitzi, D.B.: Electronic properties of the Cu2ZnSn(Se,S)4 absorber layer in solar cells as revealed by admittance spectroscopy and related methods. Appl. Phys. Lett. 100, 253905 (2012).Google Scholar
36.Duan, H.S., Yang, W., Bob, B., Hsu, C.J., Lei, B., and Yang, Y.: The role of sulfur in solution-processed Cu2ZnSn(S,Se)4 and its effect on defect properties. Adv. Funct. Mater. 23, 1466 (2013).Google Scholar
37.Persson, C.: Electronic and optical properties of Cu2ZnSnS4 and Cu2ZnSnSe4. J. Appl. Phys. 107, 053710 (2010).Google Scholar
38.Gokmen, T., Gunawan, O., and Mitzi, D.B.: Minority carrier diffusion length extraction in Cu2ZnSn(Se,S)4 solar cells. J. Appl. Phys. 114, 114511 (2013).Google Scholar
39.Gunawan, O., Gokmen, T., and Mitzi, D.B.: Copper Zinc Tin Sulphide-Based Thin Film Solar Cells (John Wiley & Sons, Hoboken, NJ, 2015).Google Scholar
40.Repins, I., Beall, C., Vora, N., DeHart, C., Kuciauskas, D., Dippo, P., To, B., Mann, J., Hsu, W.-C., and Goodrich, A.: Co-evaporated Cu2ZnSnSe4 films and devices. Sol. Energy Mater. Sol. Cells 101, 154 (2012).Google Scholar
41.Shin, B., Gunawan, O., Zhu, Y., Bojarczuk, N.A., Chey, S.J., and Guha, S.: Thin film solar cell with 8.4% power conversion efficiency using an earth-abundant Cu2ZnSnS4 absorber. Prog. Photovolt. 21, 72 (2013).Google Scholar
42.Green, M.A.: Accuracy of analytical expressions for solar cell fill factors. Sol. Cells 7, 337 (1982).Google Scholar
43.Todorov, T.K., Tang, J., Bag, S., Gunawan, O., Gokmen, T., Zhu, Y., and Mitzi, D.B.: Beyond 11% efficiency: characteristics of state-of-the-art Cu2ZnSn(S,Se)4 solar cells. Adv. Energy Mater. 3, 34 (2013).Google Scholar
44.Haight, R., Shao, X., Wang, W., and Mitzi, D.B.: Electronic and elemental properties of the Cu2ZnSn(S,Se)4 surface and grain boundaries. Appl. Phys. Lett. 104, (2014).Google Scholar
45.Bär, M., Schubert, B.-A., Marsen, B., Krause, S., Pookpanratana, S., Unold, T., Weinhardt, L., Heske, C., and Schock, H.-W.: Native oxidation and Cu-poor surface structure of thin film Cu2ZnSnS4 solar cell absorbers. Appl. Phys. Lett. 99, (2011).Google Scholar
46.Xu, P., Chen, S., Huang, B., Xiang, H.-J., Gong, X.-G., and Wei, S.-H.: Stability and electronic structure of Cu2ZnSnS4 surfaces: first-principles study. Phys. Rev. B 88, 045427 (2013).Google Scholar
47.Liao, D. and Rockett, A.: Cu depletion at the CuInSe2 surface. Appl. Phys. Lett. 82, 2829 (2003).Google Scholar
48.Schmid, D., Ruckh, M., Grunwald, F., and Schock, H.-W.: Chalcopyrite/defect chalcopyrite heterojunctions on the basis of CuInSe2. J. Appl. Phys. 73, 2902 (1993).Google Scholar
49.Jaffe, J.E. and Zunger, A.: Defect-induced nonpolar-to-polar transition at the surface of chalcopyrite semiconductors. Phys. Rev. B 64, 241304 (2001).Google Scholar
50.Liao, D. and Rockett, A.: Cd doping at the CuInSe2/CdS heterojunction. J. Appl. Phys. 93, 9380 (2003).Google Scholar
51.Migliorato, P., Shay, J., Kasper, H., and Wagner, S.: Analysis of the electrical and luminescent properties of CuInSe2. J. Appl. Phys. 46, 1777 (1975).Google Scholar
52.Maeda, T., Nakamura, S., and Wada, T.: First-principles study on Cd doping in Cu2ZnSnS4 and Cu2ZnSnSe4. Jpn. J. Appl. Phys. 51, 10NC11 (2012).Google Scholar
53.Niles, D.W., Al-Jassim, M., and Ramanathan, K.: Direct observation of Na and O impurities at grain surfaces of CuInSe2 thin films. J. Vac. Sci. Technol A 17, 291 (1999).CrossRefGoogle Scholar
54.Kronik, L., Cahen, D., and Schock, H.W.: Effects of sodium on polycrystalline Cu(In,Ga)Se2 and its solar cell performance. Adv. Mater. 10, 31 (1998).Google Scholar
55.Cahen, D. and Noufi, R.: Defect chemical explanation for the effect of air anneal on CdS/CuInSe2 solar cell performance. Appl. Phys. Lett. 54, 558 (1989).Google Scholar
56.Rockett, A.: The effect of Na in polycrystalline and epitaxial single-crystal CuIn1−x GaxSe2. Thin Solid Films 480, 2 (2005).Google Scholar
57.Oo, W.H., Johnson, J., Bhatia, A., Lund, E., Nowell, M., and Scarpulla, M.: Grain size and texture of Cu2ZnSnS4 thin films synthesized by cosputtering binary sulfides and annealing: effects of processing conditions and sodium. J. Electron. Mater. 40, 2214 (2011).Google Scholar
58.Prabhakar, T. and Jampana, N.: Effect of sodium diffusion on the structural and electrical properties of Cu2ZnSnS4 thin films. Sol. Energy Mater. Sol. Cells 95, 1001 (2011).Google Scholar
59.Nakada, T.: Invited paper: CIGS-based thin film solar cells and modules: unique material properties. Electon. Mater. Lett. 8, 179 (2012).Google Scholar
60.Rau, U. and Schock, H.W.: Electronic properties of Cu(In,Ga)Se2 heterojunction solar cells–recent achievements, current understanding, and future challenges. Appl. Phys. A 69, 131 (1999).Google Scholar
61.Zhou, H., Song, T.-B., Hsu, W.-C., Luo, S., Ye, S., Duan, H.-S., Hsu, C.-J., Yang, W., and Yang, Y.: Rational defect passivation of Cu2ZnSn(S,Se)4 photovoltaics with solution-processed Cu2ZnSnS4: Na nanocrystals. J. Am. Chem. Soc. 135, 15998 (2013).Google Scholar
62.Nagaoka, A., Miyake, H., Taniyama, T., Kakimoto, K., Nose, Y., Scarpulla, M.A., and Yoshino, K.: Effects of sodium on electrical properties in Cu2ZnSnS4 single crystal. Appl. Phys. Lett. 104, 152101 (2014).Google Scholar
63.Erslev, P.T., Lee, J.W., Shafarman, W.N., and Cohen, J.D.: The influence of Na on metastable defect kinetics in CIGS materials. Thin Solid Films 517, 2277 (2009).Google Scholar
64.Gershon, T., Shin, B., Bojarczuk, N., Hopstaken, M., Mitzi, D.B., and Guha, S.: The role of sodium as a surfactant and suppressor of non-radiative recombination at internal surfaces in Cu2ZnSnS4. Adv. Energy Mater. (2014). DOI: 10.1002/aenm.201400849.Google Scholar
65.Li, J.V., Kuciauskas, D., Young, M.R., and Repins, I.L.: Effects of sodium incorporation in Co-evaporated Cu2ZnSnSe4 thin-film solar cells. Appl. Phys. Lett. 102, 163905 (2013).Google Scholar
66.Nakada, T., Iga, D., Ohbo, H., and Kunioka, A.: Effects of sodium on Cu(In,Ga)Se2-based thin films and solar cells. Jpn. J. Appl. Phys. 36, 732 (1997).Google Scholar
67.Johnson, M., Baryshev, S., Thimsen, E., Manno, M., Zhang, X., Veryovkin, I., Leighton, C., and Aydil, E.: Alkali-metal-enhanced grain growth in Cu2ZnSnS4 thin films. Energy Environ. Sci. 7, 1931 (2014).Google Scholar
68.Yan, Y., Jiang, C.-S., Noufi, R., Wei, S.-H., Moutinho, H., and Al-Jassim, M.: Electrically benign behavior of grain boundaries in polycrystalline CuInSe2 films. Phys. Rev. Lett. 99, 235504 (2007).Google Scholar
69.Li, J., Mitzi, D.B., and Shenoy, V.B.: Structure and electronic properties of grain boundaries in earth-abundant photovoltaic absorber Cu2ZnSnSe4. ACS Nano 5, 8613 (2011).Google Scholar
70.Li, J.B., Chawla, V., and Clemens, B.M.: Investigating the role of grain boundaries in CZTS and CZTSSe thin film solar cells with scanning probe microscopy. Adv. Mater. 24, 720 (2012).Google Scholar
71.Sutter-Fella, C.M., Stu"ckelberger, J.A., Hagendorfer, H., La Mattina, F., Kranz, L., Nishiwaki, S., Uhl, A.R., Romanyuk, Y.E., and Tiwari:, A.N.Sodium assisted sintering of chalcogenides and its application to solution processed Cu2ZnSn(S,Se)4 thin film solar cells. Chem. Mater. 26, 1420 (2014).Google Scholar
72.Tomashyk, V., Feychuk, P., and Shcherbak, L.: Ternary Alloys Based on II-VI Semiconductor Compounds (Taylor & Frances Group, Boca Raton, FL, 2014).Google Scholar
73.Shin, B., Zhu, Y., Bojarczuk, N.A., Chey, S.J., and Guha, S.: Control of an interfacial MoSe2 layer in Cu2ZnSnSe4 thin film solar cells: 8.9% power conversion efficiency with a TiN diffusion barrier. Appl. Phys. Lett. 101, 053903 (2012).Google Scholar
74.Shu, Q., Yang, J.-H., Chen, S., Huang, B., Xiang, H., Gong, X.-G., and Wei, S.-H.: Cu2Zn(Sn,Ge)Se4 and Cu2Zn(Sn,Si)Se4 alloys as photovoltaic materials: structural and electronic properties. Phys. Rev. B 87, 115208 (2013).Google Scholar
75.Ford, G.M., Guo, Q., Agrawal, R., and Hillhouse, H.W.: Earth abundant element Cu2Zn(Sn1−xGex)S4 nanocrystals for tunable band gap solar cells: 6.8% efficient device fabrication. Chem. Mater. 23, 2626 (2011).Google Scholar
76.Guo, Q., Ford, G.M., Yang, W.-C., Hages, C.J., Hillhouse, H.W., and Agrawal, R.: Enhancing the performance of CZTSSe solar cells with Ge alloying. Sol. Energy Mater. Sol. Cells 105, 132 (2012).Google Scholar
77.Bag, S., Gunawan, O., Gokmen, T., Zhu, Y., and Mitzi, D.B.: Hydrazine-processed Ge-substituted CZTSe solar cells. Chem. Mater. 24, 4588 (2012).Google Scholar
78.Wang, C., Chen, S., Yang, J.-H., Lang, L., Xiang, H., Gong, X., Walsh, A., and Wei, S.-H.: Design of I2-II-IV-VI4 semiconductors through element-substitution: the thermodynamic stability limit and chemical trend. Chem. Mater. 26, 3411 (2014).Google Scholar
79.Scragg, J.J., Choubrac, L., Lafond, A., Ericson, T., and Platzer-Björkman, C.: A low-temperature order-disorder transition in Cu2ZnSnS4 thin films. Appl. Phys. Lett. 104, 041911 (2014).Google Scholar