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Origin of passivation in hole-selective transition metal oxides for crystalline silicon heterojunction solar cells

Published online by Cambridge University Press:  19 December 2016

Luis G. Gerling Open the ORCID record for Luis G. Gerling [Opens in a new window] ,
Cristobal Voz Open the ORCID record for Cristobal Voz [Opens in a new window] ,
Ramón Alcubilla Open the ORCID record for Ramón Alcubilla [Opens in a new window]  and
Joaquim Puigdollers Open the ORCID record for Joaquim Puigdollers [Opens in a new window]
Luis G. Gerling*
Affiliation:
Electronic Engineering Department, Universitat Politècnica de Catalunya, Barcelona 08034, Spain; and Centre de Recerca en Nanoenginyeria, Universitat Politécnica de Catalunya, Barcelona 08028, Spain
Cristobal Voz
Affiliation:
Electronic Engineering Department, Universitat Politècnica de Catalunya, Barcelona 08034, Spain; and Centre de Recerca en Nanoenginyeria, Universitat Politécnica de Catalunya, Barcelona 08028, Spain
Ramón Alcubilla
Affiliation:
Electronic Engineering Department, Universitat Politècnica de Catalunya, Barcelona 08034, Spain; and Centre de Recerca en Nanoenginyeria, Universitat Politécnica de Catalunya, Barcelona 08028, Spain
Joaquim Puigdollers
Affiliation:
Electronic Engineering Department, Universitat Politècnica de Catalunya, Barcelona 08034, Spain; and Centre de Recerca en Nanoenginyeria, Universitat Politécnica de Catalunya, Barcelona 08028, Spain
*
a) Address all correspondence to this author. e-mail: guillermo.gerling@upc.edu
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Abstract

Transition metal oxides (TMOs) have recently demonstrated to be a good alternative to boron/phosphorous doped layers in crystalline silicon heterojunction solar cells. In this work, the interface between n-type c-Si (n-Si) and three thermally evaporated TMOs (MoO3, WO3, and V2O5) was investigated by transmission electron microscopy, secondary ion-mass, and x-ray photoelectron spectroscopy. For the oxides studied, surface passivation of n-Si was attributed to an ultra-thin (1.9–2.8 nm) SiO x∼1.5 interlayer formed by chemical reaction, leaving oxygen-deficient species (MoO, WO2, and VO2) as by-products. Carrier selectivity was also inferred from the inversion layer induced on the n-Si surface, a result of Fermi level alignment between two materials with dissimilar electrochemical potentials (work function difference Δϕ ≥ 1 eV). Therefore, the hole-selective and passivating functionality of these TMOs, in addition to their ambient temperature processing, could prove an effective means to lower the cost and simplify solar cell processing.

Keywords

photovoltaicpassivationoxide
Type
Invited Papers
Information
Journal of Materials Research , Volume 32 , Issue 2 , 27 January 2017 , pp. 260 - 268
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Copyright
Copyright © Materials Research Society 2016 

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References

REFERENCES

Taguchi, M., Yano, A., Tohoda, S., Matsuyama, K., Nakamura, Y., Nishiwaki, T., Fujita, K., and Maruyama, E.: 24.7% Record efficiency HIT solar cell on thin silicon wafer. IEEE J. Photovoltaics 4, 96 (2014).CrossRefGoogle Scholar
Battaglia, C., Cuevas, A., and De Wolf, S.: High-efficiency crystalline silicon solar cells: Status and perspectives. Energy Environ. Sci. 9, 1552 (2016).CrossRefGoogle Scholar
Cuevas, A., Allen, T., and Bullock, J.: Skin care for healthy silicon solar cells. In 42nd IEEE PVSC (IEEE, New Orleans, LA, 2015).Google Scholar
Melskens, J., van de Loo, B.W.H., Macco, B., Vos, M.F.J., Palmans, J., Smit, S., and Kessels, E.: Concepts and prospects of passivating contacts for crystalline silicon solar cells. In 42nd IEEE PVSC (IEEE, New Orleans, LA, 2015).Google Scholar
Zielke, D., Pazidis, A., Werner, F., and Schmidt, J.: Organic-silicon heterojunction solar cells on n-type silicon wafers: The BackPEDOT concept. Sol. Energy Mater. Sol. Cells. 131, 110 (2014).CrossRefGoogle Scholar
Xu, D., Yu, X., Zuo, L., and Yang, D.: Interface engineering and efficiency improvement of monolayer graphene–silicon solar cells by inserting an ultra-thin LiF interlayer. RSC Adv. 5, 46480 (2015).CrossRefGoogle Scholar
Wan, Y., Samundsett, C., Bullock, J., Allen, T., Hettick, M., Yan, D., Zheng, P., Zhang, X., Cui, J., McKeon, J.A., Javey, A., and Cuevas, A.: Magnesium fluoride electron–selective contacts for crystalline silicon solar cells. ACS Appl. Mater. Interfaces 8, 14671 (2016).CrossRefGoogle ScholarPubMed
Um, H.D., Kim, N., Lee, K., Hwang, I., Seo, J.H., and Seo, K.: Dopant-free all-back-contact Si nanohole solar cells using MoO x and LiF films. Nano Lett. 16, 981 (2016).CrossRefGoogle Scholar
Mews, M., Korte, L., and Rech, B.: Oxygen vacancies in tungsten oxide and their influence on tungsten oxide/silicon heterojunction solar cells. Sol. Energy Mater. Sol. Cells 148, 77 (2016).CrossRefGoogle Scholar
Boccard, M., Ding, L., Koswatta, P., Bertoni, M.I., and Holman, Z.: Evaluation of metal oxides prepared by reactive sputtering as carrier-selective contacts for crystalline silicon solar cells. In 42nd IEEE PVSC (IEEE, New Orleans, 2015).Google Scholar
Bivour, M., Temmler, J., Steinkemper, H., and Hermle, M.: Molybdenum and tungsten oxide: High work function wide band gap contact materials for hole selective contacts of silicon solar cells. Sol. Energy Mater. Sol. Cells 142, 34 (2015).CrossRefGoogle Scholar
Battaglia, C., de Nicolás, S.M., De Wolf, S., Yin, X., Zheng, M., Ballif, C., and Javey, A.: Silicon heterojunction solar cell with passivated hole selective MoO x contact. Appl. Phys. Lett. 104, 113902 (2014).CrossRefGoogle Scholar
Bullock, J., Hettick, M., Geissbühler, J., Ong, A.J., Allen, T., Sutter-Fella, C.M., Chen, T., Ota, H., Schaler, E.W., De Wolf, S., Ballif, C., Cuevas, A., and Javey, A.: Efficient silicon solar cells with dopant-free asymmetric heterocontacts. Nat. Energy 1, 15031 (2016).CrossRefGoogle Scholar
Yoon, W., Cho, E., Myers, J.D., Ok, Y-W., Lumb, M.P., Frantz, J.A., Kotulak, N.A., Scheiman, D., Jenkins, P.P., Rohatgi, A., and Walters, R.J.: Transparent conducting oxide-based, passivated contacts for high efficiency crystalline Si solar cells. In 42nd IEEE PVSC (IEEE, New Orleans, LA, 2015).Google Scholar
Islam, R., Shine, G., and Saraswat, K.C.: Schottky barrier height reduction for holes by Fermi level depinning using metal/nickel oxide/silicon contacts. Appl. Phys. Lett. 105, 182103 (2014).CrossRefGoogle Scholar
Gerling, L.G., Mahato, S., Morales-Vilches, A., Masmitja, G., Ortega, P., Voz, C., Alcubilla, R., and Puigdollers, J.: Transition metal oxides as hole-selective contacts in silicon heterojunctions solar cells. Sol. Energy Mater. Sol. Cells. 145, 109 (2016).CrossRefGoogle Scholar
Liao, B., Hoex, B., Aberle, A.G., Chi, D., and Bhatia, C.S.: Excellent c-Si surface passivation by low-temperature atomic layer deposited titanium oxide. Appl. Phys. Lett. 104, 253903 (2014).CrossRefGoogle Scholar
Yang, X., Bi, Q., Ali, H., Davis, K., Schoenfeld, W.V., and Weber, K.: High-performance TiO2-based electron-selective contacts for crystalline silicon solar cells. Adv. Mater. 28, 5891 (2016).CrossRefGoogle ScholarPubMed
Greiner, M.T. and Lu, Z-H.: Thin-film metal oxides in organic semiconductor devices: Their electronic structures, work functions and interfaces. NPG Asia Mater. 5, e55 (2013).CrossRefGoogle Scholar
Gerling, L.G., Masmitja, G., Voz, C., Ortega, P., Puigdollers, J., and Alcubilla, R.: Back junction n-type silicon heterojunction solar cells with V2O5 hole-selective contact. Energy Procedia 92, 633 (2016).CrossRefGoogle Scholar
Geissbühler, J., Werner, J., Martin de Nicolas, S., Barraud, L., Hessler-Wyser, A., Despeisse, M., Nicolay, S., Tomasi, A., Niesen, B., De Wolf, S., and Ballif, C.: 22.5% efficient silicon heterojunction solar cell with molybdenum oxide hole collector. Appl. Phys. Lett. 107, 081601 (2015).CrossRefGoogle Scholar
DeBenedetti, W.J.I. and Chabal, Y.J.: Functionalization of oxide-free silicon surfaces. J. Vac. Sci. Technol., A 31, 050826 (2013).CrossRefGoogle Scholar
Bullock, J., Cuevas, A., Allen, T., and Battaglia, C.: Molybdenum oxide MoO x : A versatile hole contact for silicon solar cells. Appl. Phys. Lett. 105, 232109 (2014).CrossRefGoogle Scholar
Meyer, J., Hamwi, S., Kröger, M., Kowalsky, W., Riedl, T., and Kahn, A.: Transition metal oxides for organic electronics: Energetics, device physics and applications. Adv. Mater. 24, 5408 (2012).CrossRefGoogle ScholarPubMed
Schewchun, J., Singh, R., and Green, M.: Theory of metal-insulator-semiconductor solar cells. J. Appl. Phys. 48, 765 (1977).CrossRefGoogle Scholar
Kanyal, S.S., Jensen, D.S., Zhu, Z., and Linford, M.R.: Silicon (100)/SiO2 by ToF-SIMS. Surf. Sci. Spectra 22, 1 (2015).CrossRefGoogle Scholar
Weinberger, B.R., Peterson, G.G., Eschrich, T.C., and Krasinski, H.A.: Surface chemistry of HF passivated silicon—X ray photoelectron and ion scattering spectroscopy results. J. Appl. Phys. 60, 3232 (1986).CrossRefGoogle Scholar
Wilk, G.D., Wallace, R.M., and Anthony, J.M.: High-k gate dielectrics: Current status and materials properties considerations. J. Appl. Phys. 89, 5243 (2001).CrossRefGoogle Scholar
Werner, F., Veith, B., Zielke, D., Kühnemund, L., Tegenkamp, C., Seibt, M., Brendel, R., and Schmidt, J.: Electronic and chemical properties of the c-Si/Al2O3 interface. J. Appl. Phys. 109, 2 (2011).CrossRefGoogle Scholar
Li, X.L., Xiang, W.F., Lu, H.B., and Mai, Z.H.: Studies of the interfacial structure of LaAlO3 thin films on silicon by x-ray reflectivity and angle-resolved x-ray photoelectron spectroscopy. J. Appl. Phys. 97, 124104 (2005).CrossRefGoogle Scholar
Reed, T.B.: Free Energy of Formation of Binary Compounds: An Atlas of Charts for High-temperature Chemical Calculations (MIT Press, Cambridge, MA, 1971).Google Scholar
Himpsel, F.J., McFeely, F.R., Taleb-Ibrahimi, A., and Yarmoff, J.A.: Microscopic structure of the SiO2/Si interface. Phys. Rev. B: Condens. Matter Mater. Phys. 38, 6084 (1988).CrossRefGoogle ScholarPubMed
Biesinger, M.C., Lau, L.W.M., Gerson, A.R., and Smart, R.S.C.: Resolving surface chemical states in XPS analysis of first row transition metals, oxides and hydroxides: Sc, Ti, V, Cu and Zn. Appl. Surf. Sci. 257, 887 (2010).CrossRefGoogle Scholar
Greiner, M.T., Chai, L., Helander, M.G., Tang, W-M., and Lu, Z-H.: Metal/metal–oxide interfaces: How metal contacts affect the work function and band structure of MoO3 . Adv. Funct. Mater. 23, 215 (2013).CrossRefGoogle Scholar
Gerling, L.G., Mahato, S., Voz, C., Alcubilla, R., and Puigdollers, J.: Characterization of transition metal oxide/silicon heterojunctions for solar cell applications. Appl. Sci. 5, 695 (2015).CrossRefGoogle Scholar
Ding, L., Boccard, M., Holman, Z.C., and Bertoni, M.I.: Evaluation of transition metal oxides as carrier-selective contacts for silicon heterojunction solar cells. Presented at the 2015 MRS Spring Meeting & Exhibit, San Francisco, CA, 2015.Google Scholar
Liang, Z., Su, M., Zhou, Y., Gong, L., Zhao, C., Chen, K., Xie, F., Zhang, W., Chen, J., Liu, P., and Xie, W.: Interaction at the silicon/transition metal oxide heterojunction interface and its effect on the photovoltaic performance. Phys. Chem. Chem. Phys. 17, 27409 (2015).CrossRefGoogle ScholarPubMed
Greiner, M.T., Helander, M.G., Bin Wang, Z., Tang, W.M., and Lu, Z.H.: Effects of processing conditions on the work function and energy-level alignment of NiO thin films. J. Phys. Chem. C. 114, 19777 (2010).CrossRefGoogle Scholar
Guo, Y. and Robertson, J.: Origin of the high work function and high conductivity of MoO3 . Appl. Phys. Lett. 105, 222110 (2014).CrossRefGoogle Scholar
Hermann, K., Witko, M., Druzinic, R., Chakrabarti, A., Tepper, B., Elsner, M., Gorschlüter, A., Kuhlenbeck, H., and Freund, H-J.: Properties and identification of oxygen sites at the V2O5(010) surface: Theoretical cluster studies and photoemission experiments. J. Electron Spectrosc. Relat. Phenom. 98–99, 245–256 (1999).CrossRefGoogle Scholar
Gleason-Rohrer, D.C., Brunschwig, B.S., and Lewis, N.S.: Measurement of the band bending and surface dipole at chemically functionalized Si(111)/vacuum interfaces. J. Phys. Chem. C 117, 18031 (2013).CrossRefGoogle Scholar
Bisquert, J.: Nanostructured Energy Devices: Equilibrium Concepts and Kinetics (CRC Press, Boca Raton, FL, 2014).CrossRefGoogle Scholar
Wurfel, U., Cuevas, A., and Wurfel, P.: Charge carrier separation in solar cells. IEEE J. Photovoltaics 5, 461 (2015).CrossRefGoogle Scholar
Irfan, I., Zhang, M., Ding, H., Tang, C.W., and Gao, Y.: Strong interface p-doping and band bending in C60 on MoO x . Org. Electron. 12, 1588 (2011).CrossRefGoogle Scholar