Skip to main content
SpringerLink
Log in

Optical properties of ZnO/Al/ZnO multilayer films for large area transparent electrodes

  • Articles
  • Published:
Journal of Materials Research Aims and scope Submit manuscript

Abstract

This study presents the optical properties of layered ZnO/Al/ZnO composite thin films that are being explored for potential applications in solar cells and light emitting devices. The composite thin films are explored as alternatives to ZnO thin films. They are produced via radio frequency magnetron sputtering. The study clarifies the role of the aluminum mid-layer in a ZnO (25 nm)/Al/ZnO (25 nm) film structure. Multilayers with low resistivity ∼362 µΩ cm and average transmittances between ∼85 and 90% (in the visible region of the solar spectrum) are produced. The highest Haacke figure of merit of 4.72 × 10−3 Ω−1 was obtained in a multilayer with mid-layer Al thickness of 8 nm. The combined optical band gap energy of the multilayered films increased by ∼0.60 eV for mid-layer Al thicknesses between ∼1 and 10 nm. The observed shifts in the optical absorption edges to shorter wave lengths of the spectrum are shown to be in agreement with the Moss–Burstein effect.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

FIG. 1
FIG. 2
FIG. 3
FIG. 4
FIG. 5

Similar content being viewed by others

References

  1. K.L. Chopra, S. Major, and D.K. Pandya: Transparent conductors–A status review. Thin Solid Films 102, 1–46 (1983).

    CAS  Google Scholar 

  2. F. Pan, S. Gao, C. Chen, C. Song, and F. Zeng: Recent progress in resistive random access memories: Materials, switching mechanisms, and performance. Mater. Sci. Eng., R 83, 1–59 (2014).

    Google Scholar 

  3. K. Sivaramakrishnan and T.L. Alford: Conduction and transmission analysis in gold nanolayers embedded in zinc oxide for flexible electronics. Appl. Phys. Lett. 96, 201109 (2010).

    Google Scholar 

  4. M. Hadis and Ö. Ümit: ZnO Oxide Fundamentals, Materials and Device Technology (WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 2009).

    Google Scholar 

  5. M.F. Al-Kuhaili, M.A. Al-Maghrabi, S.M.A. Durrani, and I.A. Bakhtiari: Investigation of ZnO/Al/ZnO multilayers as transparent conducting coatings. J. Phys. D: Appl. Phys. 41, 215302 (2008).

    Google Scholar 

  6. Dhananjay, J. Nagaraju, and S.B. Krupenidhi: Off-centered polarization and ferroelectric phase transition in Li-doped ZnO thin films grown by pulsed-laser ablation. J. Appl. Phys. 101, 104104 (2007).

    Google Scholar 

  7. S.J. Pearton, D.P. Norton, Y.W. Heo, and T. Steiner: Recent progress in processing and properties of ZnO. Prog. Mater. Sci. 50, 293–340 (2005).

    CAS  Google Scholar 

  8. W. Xudong, S. Jinhui, L. Jin, and L.W. Zhong: Direct-current nanogenerator driven by ultrasonic waves. Science 316, 102 (2007).

    Google Scholar 

  9. C.Y. Yang, C. Song, F. Zeng, and F. Pan: Giant piezoelectric d33 coefficient in ferroelectric vanadium doped ZnO films. Appl. Phys. Lett. 90, 242903 (2008).

    Google Scholar 

  10. C.Y. Yang, C. Song, F. Zeng, and F. Pan: V5+ ionic displacement induced ferroelectric behavior in V-doped ZnO films. Appl. Phys. Lett. 90, 242903 (2007).

    Google Scholar 

  11. A. Onodera, N. Tamaki, Y. Kawamura, S.T.K. Jin, and H. Yamashita: Dielectric activity and ferroelectricity in piezoelectric semiconductor Li-doped ZnO. J. Appl. Phys. 35, 5160–5162 (1996).

    CAS  Google Scholar 

  12. A. Onodera, N. Tamaki, K. Jin, and H. Yamashita: Ferroelectric properties in piezoelectric semiconductor Zn1-xMxO (M=Li, Mg). J. Appl. Phys. 36, 6008–6011 (1997).

    CAS  Google Scholar 

  13. D. Song, A.G. Aberle, and J. Xia: Optimisation of ZnO: Al films by change of sputter gas pressure for solar cell application. Appl. Surf. Sci. 195, 291–296 (2002).

    CAS  Google Scholar 

  14. S.S. Lin, J.L. Huang, and D.F. Lii: Effect of substrate temperature on the properties of Ti-doped ZnO films by simultaneous RF and DC magnetron sputtering. Mater. Chem. Phys. 90, 22–30 (2005).

    CAS  Google Scholar 

  15. J. Tsujinoa, N. Hommaa, S. Tomoaki, S. Isao, and A. Yoshihiko: Preparation of Al-doped ZnO thin films by RF thermal plasma evaporation. Thin Solid Films 407, 86–91 (2002).

    Google Scholar 

  16. A.F. Aktaruzzaman, G.L. Sharma, and L.K. Mahgotra: Electrical, optical and annealing characteristics of ZnO: Al films prepared by spray pyrolysis. Thin Solid Films 198, 67–74 (1991).

    CAS  Google Scholar 

  17. T. Nakada, O. Yukiyasu, M. Naoki, and K. Akio: Transparent conducting boron-doped zinc oxide films deposited by DC-magnetron sputtering in B2H6-Ar mixture. Appl. Phys. 34, 3623–3627 (1995).

    CAS  Google Scholar 

  18. H.A. Gomez, J.P. Maldonado, R. Asomoza, E.P. Zironi, J. Canetas-Ortega, and J. Palacios-Gomez: Characterization of indium-doped zinc oxide films deposited by pyrolytic spray with different indium compounds as dopants. Thin Solid Films 293, 117–123 (1997).

    CAS  Google Scholar 

  19. A. Tiburcio-Silver and A. Avila-Garcia: Properties of gallium-doped ZnO deposited onto glass by spray pyrolysis. Sol. Energy Mater. Sol. Cells 55, 3–10 (1998).

    CAS  Google Scholar 

  20. S-H. Park, H-M. Kim, B-R. Rhee, E-Y. Ko, and S-H. Shon: Effects of oxygen concentration on characteristics of RF-sputtered In2O3-ZnO thin films. Jpn. J. Appl. Phys. 40, 1429–1430 (2001).

    CAS  Google Scholar 

  21. D.R. Sahu, S-Y. Lin, and J-L. Huang: ZnO/Ag/ZnO multilayer films for the application of a very low resistance transparent electrode. Appl. Surf. Sci. 252, 7509–7514 (2006).

    CAS  Google Scholar 

  22. D.R. Sahu and J-L. Huang: Design of ZnO/Ag/ZnO multilayer transparent conductive films. Mater. Sci. Eng., B 130, 295–299 (2006).

    CAS  Google Scholar 

  23. E. Ando and M. Miyazaki: Moisture resistance of the low-emissivity coatings with a layer structure of Al-doped ZnO/Ag/Al-doped ZnO. Thin Solid Films 392, 289–293 (2001).

    CAS  Google Scholar 

  24. M. Bender, W. Seelig, C. Daube, H. Frankenberger, B. Ocker, and J. Stollenwerk: Dependence of film composition and thicknesses on optical and electrical properties of ITO–metal–ITO multilayers. Thin Solid Films 326, 67–71 (1998).

    CAS  Google Scholar 

  25. A. Feltrin and A. Freundlich: Material considerations for terawatt level deployment of photovoltaics. Renewable Energy 33, 180–185 (2008).

    CAS  Google Scholar 

  26. A. Dhar and T.L. Alford: High quality transparent TiO2/Ag/TiO2 composite electrode films deposited on flexible substrate at room temperature by sputtering. APL Mater. 1, 012102 (2013).

    Google Scholar 

  27. K.H. Choi, J.Y. Kim, Y.S. Lee, and H.J. Kim: ITO/Ag/ITO multilayer films for the application of a very low resistance transparent electrode. Thin Solid Films 341, 152–155 (1999).

    CAS  Google Scholar 

  28. A. Klöppel, W. Kriegseis, B.K. Meyer, A. Scharmann, C. Daube, J. Stollenwerk, and J. Trube: Dependence of the electrical and optical behaviour of ITO-silver-ITO multilayers on the silver properties. Thin Solid Films 365, 139–146 (2000).

    Google Scholar 

  29. M. Fahland, P. Karlsson, and C. Charton: Low resistivity transparent electrodes for displays on polymer substrates. Thin Solid Films 392, 334–337 (2001).

    CAS  Google Scholar 

  30. A. Klöppel, B. Meyer, and J. Trube: Influence of substrate temperature and sputtering atmosphere on electrical and optical properties of double silver layer systems. Thin Solid Films 392, 311–314 (2001).

    Google Scholar 

  31. M. Sawada, M. Higuchi, S. Kondo, and H. Saka: Characteristics of indium-tin-oxide/silver/indium-tin-oxide sandwich films and their application to simple liquid-crystal displays. Jpn. J. Appl. Phys. 40, 3332–3336 (2001).

    CAS  Google Scholar 

  32. Y.S. Jung, Y.W. Choi, H.C. Lee, and D.W. Lee: Effects of thermal treatment on the electrical and optical properties of silver-based indium tin oxide/metal/indium tin oxide structures. Thin Solid Films 440, 278–284 (2003).

    CAS  Google Scholar 

  33. D.R. Sahu and J.L. Huang: High quality transparent conductive ZnO/Ag/ZnO multilayer films deposited at room temperature. Thin Solid Films 515, 876–879 (2006).

    CAS  Google Scholar 

  34. D.R. Sahu and J.L. Huang: Characteristics of ZnO-Cu-ZnO multilayer films on copper layer properties. Appl. Surf. Sci. 253, 827–832 (2006).

    CAS  Google Scholar 

  35. D.R. Sahu and J.L. Huang: Dependence of film thickness on the electrical and optical properties of ZnO-Cu-ZnO multilayers. Appl. Surf. Sci. 253, 915–918 (2006).

    CAS  Google Scholar 

  36. A. Halpern and E. Erlbach: Chapter 5: Simple electric circuits. In Theory and Problems of Beginning Physics II Waves, Electromagnetism, Optics and Modern Physics (McGraw-Hill, New York, NY, 1998), p. 141.

    Google Scholar 

  37. Sleepless Media: Current metal prices. Mining journal ICMJ (2009). [Online]. Available: http://www.icmj.com/current-metal-prices.php. [Accessed 7 March 2014].

  38. S.N. Bai and T.Y. Tseng: Electrical and optical properties of ZnO: Al thin films grown by magnetron sputtering. J. Mater. Sci.: Mater. Electron. 20, 253–256 (2009).

    CAS  Google Scholar 

  39. G. Luka, T.A. Krajewski, B.S. Witkowski, G. Wisz, I.S. Virt, E. Guziewicz, and M. Godlewski: Aluminum-doped zinc oxide films grown by atomic layer deposition for transparent electrode applications. J. Mater. Sci.: Mater. Electron. 22, 1810–1815 (2011).

    CAS  Google Scholar 

  40. Y. Bouznit, Y. Beggah, and K. Djessas: RF magnetron sputtering of ZnO and Al-doped ZnO films from ceramic and nanopowder targets: A comparative study. J. Sol-Gel Sci. Technol. 61, 449–454 (2012).

    CAS  Google Scholar 

  41. E. Burstein: Anomalous optical absorption limit in InSb. Phys. Rev. 93, 632–633 (1954).

    CAS  Google Scholar 

  42. J.M. Bennett: Polarization. In Hand Book of Optics: Fundamentals, Techniques and Design, 2nd ed. (McGraw-Hill, New York, NY, 1995), Vol. I, Chapter 5.

    Google Scholar 

  43. K.L. Chopra and S.K. Bahl: Structural, electrical and optical properties of amorphous germanium films. Phys. Rev. B 1, 2545–2556 (1970).

    Google Scholar 

  44. V.V. Filippov and B.G. Shulitskii: Optical modeling and optimization of multilayer organic photovoltaic cells. J. Appl. Spectrosc. 77, 266–272 (2010).

    CAS  Google Scholar 

  45. N.M. Khusayfan and M.M. El-Nahass: Study of structure and electro-optical characteristics of indium tin oxide thin films. Adv. Condens. Matter Phys. 2013, 5 (2013).

    Google Scholar 

Download references

ACKNOWLEDGMENTS

The research was supported by grants from the World Bank STEP-B Program, the World Bank African Centers of Excellence Program, the African Development Bank, the African Capacity Building Foundation, and the Nelson Mandela Institution. Appreciation is also extended to Mrs. K. Onogu of Physics Advanced Laboratory, SHESTCO, Nigeria, for technical assistance with laboratory techniques.

Author information

Authors and Affiliations

  1. Department of Materials Science and Engineering, African University of Science and Technology (AUST), PMB 681, Garki, Abuja, Nigeria

    Egidius Rutatizibwa Rwenyagila, Benjamin Agyei-Tuffour & Winston Oluwole Soboyejo

  2. Physics Department, University of Dar es Salaam, Dar es Salaam, 35063, Tanzania

    Egidius Rutatizibwa Rwenyagila

  3. Physics Advanced Laboratory, Sheda Science and Technology Complex (SHESTCO), Abuja, Nigeria

    Martiale Gaetan Zebaze Kana

  4. Department of Materials Science and Engineering, Kwara State University, PMB 1531, Malete, Nigeria

    Martiale Gaetan Zebaze Kana

  5. Department of Theoretical and Applied Physics, African University of Science and Technology (AUST), PMB 681, Garki, Abuja, Nigeria

    Omololu Akin-Ojo

  6. Department of Mechanical and Aerospace Engineering & the Princeton Institute of Science and Technology of Materials, Princeton University, Princeton, New Jersey, 08544, USA

    Winston Oluwole Soboyejo

Authors
  1. Egidius Rutatizibwa Rwenyagila
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Benjamin Agyei-Tuffour
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Martiale Gaetan Zebaze Kana
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Omololu Akin-Ojo
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Winston Oluwole Soboyejo
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Winston Oluwole Soboyejo.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Rwenyagila, E.R., Agyei-Tuffour, B., Zebaze Kana, M.G. et al. Optical properties of ZnO/Al/ZnO multilayer films for large area transparent electrodes. Journal of Materials Research 29, 2912–2920 (2014). https://doi.org/10.1557/jmr.2014.298

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1557/jmr.2014.298

Search

Navigation