Metal-sandwiched zinc oxide (ZnO)/titanium (Ti)/copper (Cu)/Ti/ZnO thin film systems were fabricated using magnetron sputtering technology and then annealed using a rapid thermal annealing system at temperatures from 100 to 400°C. The influence of the Ti film thicknesses and annealing temperatures on the surface morphologies, sheet resistance and optical properties were studied. The surface morphologies change a little with the annealing temperature rises. The sheet resistances reduce with the Ti film thickness or annealing temperature increasing. Both the max transmittance and figure of merit reduce with the increase of Ti film thickness. The max transmittance increases with the temperature increasing from 100 to 300°C and then reduces. However, the figure of merit increases with the temperature increasing which indicates that the metal-sandwiched ZnO/Ti/Cu/Ti/ZnO thin film system annealed at 400°C has the optimal performance.

References

1. 1)
  - 30. Lisiecki, I., Billoudet, F., Pileni, M.P., et al: ‘Control of the shape and the size of copper metallic particles’, J. Phys. Chem., 1996, 100, (10), pp. 4160–4166 (doi: 10.1021/jp9523837).
2. 2)
  - 10. Yu, S.H., Jia, H.W., Zheng, H.W., et al: ‘High quality transparent conductive SnO2/Ag/SnO2 tri-layer films deposited at room temperature by magnetron sputtering’, Mater. Lett., 2012, 85, pp. 68–70 (doi: 10.1016/j.matlet.2012.06.108).
3. 3)
  - 14. Kim, D.: ‘Influence of CuSn thickness on the work function and optoelectrical properties of ZnO/CuSn/ZnO multilayer films’, Displays, 2010, 31, (3), pp. 155–159 (doi: 10.1016/j.displa.2010.05.002).
4. 4)
  - 28. Sivaramakrishnan, K., Theodore, N.D., Moulder, J.F., et al: ‘The role of copper in ZnO/Cu/ZnO thin films for flexible electronics’, J. Appl. Phys., 2009, 106, p. 063510 (doi: 10.1063/1.3213385).
5. 5)
  - 18. Hadri, A., Taibi, M., Loghmarti, M., et al: ‘Development of transparent conductive indium and fluorine co-doped ZnO thin films: effect of F concentration and post-annealing temperature’, Thin Solid Films, 2017, 601, pp. 7–12 (doi: 10.1016/j.tsf.2015.11.036).
6. 6)
  - 15. Sarma, B., Sarma, B.K.: ‘Role of residual stress and texture of ZnO nanocrystals on electro-optical properties of ZnO/Ag/ZnO multilayer transparent conductors’, J. Alloys Compd., 2018, 734, pp. 210–219 (doi: 10.1016/j.jallcom.2017.11.028).
7. 7)
  - 9. Wei, W.Z., Hong, R.J., Wang, J.X., et al: ‘Electron-beam irradiation induced optical transmittance enhancement for Au/ITO and ITO/Au/ITO multilayer thin films’, J. Mater. Sci. Technol., 2017, 33, (10), pp. 1107–1112 (doi: 10.1016/j.jmst.2017.07.006).
8. 8)
  - 20. Kwon, J., Cho, H., Suh, Y.D., et al: ‘Flexible and transparent Cu electronics by low-temperature acid-assisted laser processing of Cu nanoparticles’, Adv. Mater. Technol., 2017, 2, No. 1600222, pp. 1–8.
9. 9)
  - 1. Kang, H., Lu, Z., Zhong, Z., et al: ‘Structural, optical and electrical characterization of Ga–Mg co-doped ZnO transparent conductive films’, Mater. Lett., 2018, 215, pp. 102–105 (doi: 10.1016/j.matlet.2017.12.072).
10. 10)
  - 4. Yao, Z.R., Li, S., Cai, H.L., et al: ‘Improved indium oxide transparent conductive thin films by hydrogen annealing’, Mater. Lett., 2017, 208, pp. 107–110 (doi: 10.1016/j.matlet.2017.04.151).
11. 11)
  - 13. Yu, S.H., Liu, Y.F., Zheng, H.R., et al: ‘Improved performance of transparent-conducting AZO/Cu/AZO multilayer thin films by inserting a metal Ti layer for flexible electronics’, Opt. Lett., 2017, 42, pp. 3020–3023 (doi: 10.1364/OL.42.003020).
12. 12)
  - 1. Kwon, J.: ‘Low-temperature oxidation-free selective laser sintering of Cu nanoparticle paste on a polymer substrate for the flexible touch panel applications’, ACS Appl. Mater. Interfaces, 2016, 8, (18), pp. 11575–11582 (doi: 10.1021/acsami.5b12714).
13. 13)
  - 31. Sivaramakrishnan, K., Alford, T.L.: ‘Metallic conductivity and the role of copper in ZnO/Cu/ZnO thin films for flexible electronics’, Appl. Phys. Lett., 2009, 94, p. 052104 (doi: 10.1063/1.3077184).
14. 14)
  - 25. Song, S.M., Yang, T.L., Lv, M.S., et al: ‘Effect of Cu layer thickness on the structural, optical and electrical properties of AZO/Cu/AZO tri-layer films’, Vacuum, 2010, 85, pp. 39–44 (doi: 10.1016/j.vacuum.2010.03.008).
15. 15)
  - 24. Ghosh, D.S., Chen, T.L., Pruneri, V.: ‘Ultrathin Cu-Ti bilayer transparent conductors with enhanced figure-of-merit and stability’, Appl. Phys. Lett., 2016, 96, p. 091106 (doi: 10.1063/1.3341201).
16. 16)
  - 5. Fardad, S., Ramos, E.A., Salandrino, A.: ‘Accumulation-layer surface plasmons in transparent conductive oxides’, Opt. Lett., 2017, 42, (10), pp. 2038–2041 (doi: 10.1364/OL.42.002038).
17. 17)
  - 27. Sahu, D.R., Huang, J.L.: ‘Dependence of film thickness on the electrical and optical properties of ZnO–Cu–ZnO multilayers’, Appl. Surf. Sci., 2006, 253, pp. 915–918 (doi: 10.1016/j.apsusc.2006.01.035).
18. 18)
  - 16. Lin, Q.J., Yang, S.M., Jing, W.X., et al: ‘Numerical simulation on optical characteristics of ZnO/Cu/ZnO thin film’, J. Nanosci. Nanotech., 2016, 16, pp. 873–877 (doi: 10.1166/jnn.2016.10635).
19. 19)
  - 7. Sharma, V., Kumar, P., Kumar, A., et al: ‘High-performance radiation stable ZnO/Ag/ZnO multilayer transparent conductive electrode’, Sol. Energy Mat. Sol. C., 2017, 169, pp. 122–131 (doi: 10.1016/j.solmat.2017.05.009).
20. 20)
  - 19. Nanoune, A., Touam, T., Chelouche, A.: ‘Thickness, annealing and substrate effects on structural, morphological, optical and wave guiding properties of RF sputtered ZnO thin films’, J. Mater. Sci. Mater. El., 2017, 28, pp. 12207–12219 (doi: 10.1007/s10854-017-7036-x).
21. 21)
  - 17. Wang, L.W., Chen, W.D., Li, L.: ‘Investigation of the optical and electrical properties of ZnO/Cu/ZnO multilayer structure for transparent conductive electrodes by magnetron sputtering’, J. Mater. Sci. Mater. El., 2017, 28, pp. 3458–3466 (doi: 10.1007/s10854-016-5943-x).
22. 22)
  - 3. Aydin, E., Sankir, N.D.: ‘AZO/metal/AZO transparent conductive oxide thin films for spray pyrolyzed copper indium sulfide based solar cells’, Thin Solid Films, 2018, 653, pp. 29–36 (doi: 10.1016/j.tsf.2018.03.012).
23. 23)
  - 26. Chen, P.S., Peng, C.H., Chang, Y.W., et al: ‘Improved indium-free transparent ZnO/metal/ZnO electrode through a statistical experimental design method’, Adv. Mater. Sci. Eng., 2016, 2016, p. 7258687.
24. 24)
  - 6. Yoo, J.H., Matthews, M., Ramsey, P., et al: ‘Thermally ruggedized ITO transparent electrode films for high power optoelectronics’, Opt. Express, 2017, 25, (21), pp. 25533–25545 (doi: 10.1364/OE.25.025533).
25. 25)
  - 5. Lee, J., Lee, P., Lee, H., et al: ‘Very long Ag nanowire synthesis and its application in a highly transparent, conductive and flexible metal electrode touch panel’, Nanoscale, 2012, 4, pp. 6408–6414 (doi: 10.1039/c2nr31254a).
26. 26)
  - 2. Chen, C., Zhao, Y., Wei, W., et al: ‘Fabrication of silver nanowire transparent conductive films with an ultra-low haze and ultra-high uniformity and their application in transparent electronics’, J. Mater. Chem. C, 2017, 5, pp. 2240–2246 (doi: 10.1039/C6TC05455B).
27. 27)
  - 22. Han, S., Hong, S., Ham, J., et al: ‘Fast plasmonic laser nanowelding for a Cu-nanowire percolation network for flexible transparent conductors and stretchable electronics’, Adv. Mater., 2014, 26, pp. 5808–5814 (doi: 10.1002/adma.201400474).
28. 28)
  - 11. Yu, S.H., Zhang, W.F., Li, L.X., et al: ‘Optimization of SnO2/Ag/SnO2 tri-layer films as transparent composite electrode with high figure of merit’, Thin Solid Films, 2014, 552, pp. 150–154 (doi: 10.1016/j.tsf.2013.11.109).
29. 29)
  - 8. Ko, Y.D., Kim, J.Y., Joung, H.C., et al: ‘Low temperature deposited transparent conductive ITO and IZTO films for flat panel display applications’, J. Ceram. Process. Res., 2013, 14, (2), pp. 183–187.
30. 30)
  - 12. Yu, S.H., Li, L.X., Xu, D., et al: ‘Characterization of SnO2/Cu/SnO2 multilayers for high performance transparent conducting electrodes’, Thin Solid Films, 2014, 562, pp. 501–505 (doi: 10.1016/j.tsf.2014.04.064).
31. 31)
  - 29. Haacke, G.: ‘New figure of merit for transparent conductors’, J. Appl. Phys., 1976, 47, pp. 4086–4089 (doi: 10.1063/1.323240).

Electrical and optical properties of metal-sandwiched ZnO/Ti/Cu/Ti/ZnO transparent conductive thin film

References

Related content