Research article
Physical properties of spin-coated nanocrystalline zinc oxide thin film
- 1 Faculty of Materials and Manufacturing Technologies, Malek Ashtar University of Technology, Tehran, Iran
Abstract
ZnO, in its wurtzite structure, is a widely studied metal oxide due to its unique optical and electronic properties, including efficient excitonic emission at room temperature. Zinc oxide thin films were synthesized through the dehydration of various precursors. In ethanol and mono-ethanolamine, zinc acetate (I) and zinc nitrate (II) were dissolved. Glass substrates were coated using the sol-gel spin coating method (3000 rpm for 10 s), followed by heating at 250 °C. This process was done five times to make the films thicker (and allow them to form five layers on the substrate), and then they were annealed at 450 °C for 3 hours in air, yielding 200 nm-thick films. Where acetate-derived ZnO demonstrated superior performance: 92% optical transmission at 1100 nm (vs. 80% for nitrate), a widened bandgap (3.3 eV), and enlarged crystallite size (74 nm), attributed to reduced defect density and homogeneous morphology. The presence of various vibration modes in the prepared samples was also revealed by Raman spectroscopy (RS) of the annealed films. The presence of concentrated stresses within the coated films is also determined using RS, and the scanning electron microscopy results confirm the Raman E2 peaks by FE-SEM images.
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Keywords:
Thin films, Zinc oxide, Band gap, Sol-gel, Spin coating
References
[1] M.A. Borysiewicz, ZnO as a functional material, a review, Crystals. 9 (2019) 505. https://doi.org/10.3390/cryst9100505.
[2] M.T. Noman, N. Amor, M. Petru, Synthesis and applications of ZnO nanostructures (ZONSs): A review, Crit. Rev. Solid State Mater. Sci. 47 (2022) 99–141. https://doi.org/10.1080/10408436.2021.1886041.
[3] D.K. Sharma, S. Shukla, K.K. Sharma, V. Kumar, A review on ZnO: Fundamental properties and applications, Mater. Today Proc. 49 (2022) 3028–3035. https://doi.org/10.1016/j.matpr.2020.10.238.
[4] P. Kumar, Nisha, P. Sarkar, S. Singh, B. Mishra, R.S. Katiyar, The influence of post-growth heat treatment on the optical properties of pulsed laser deposited ZnO thin films, Appl. Phys. A. 128 (2022) 372. https://doi.org/10.1007/s00339-022-05511-2.
[5] S. Flickyngerova, K. Shtereva, V. Stenova, D. Hasko, I. Novotny, et al., Structural and optical properties of sputtered ZnO thin films, Appl. Surf. Sci. 254 (2008) 3643–3647. https://doi.org/10.1016/S0040-6090(99)00060-7.
[6] M. Opel, S. Geprägs, M. Althammer, T. Brenninger, R. Gross, Laser molecular beam epitaxy of ZnO thin films and heterostructures, J. Phys. D: Appl. Phys. 47 (2013) 034002. https://doi.org/10.1088/0022-3727/47/3/034002.
[7] T.M. Barnes, J. Leaf, C. Fry, C.A. Wolden, Room temperature chemical vapor deposition of c-axis ZnO, J. Cryst. Growth. 274 (2005) 412–417. https://doi.org/10.1016/j.jcrysgro.2004.10.015.
[8] Y.-S. Ho, K.-Y. Lee, Fabrication of highly oriented (002) ZnO film on glass by sol–gel method, Thin Solid Films. 519 (2010) 1431–1434. https://doi.org/10.1016/j.tsf.2010.09.006.
[9] A. Abdel-Galil Farrag, M.R. Balboul, Nano ZnO thin films synthesis by sol–gel spin coating method as a transparent layer for solar cell applications, J. Sol-Gel Sci. Technol. 82 (2017) 269–279. https://doi.org/10.1007/s10971-016-4277-8.
[10] M.A. Shafi, A. Bouich, K. Fradi, J.M. Guaita, L. Khan, B. Mari, Effect of deposition cycles on the properties of ZnO thin films deposited by spin coating method for CZTS-based solar cells, Optik. 258 (2022) 168854. https://doi.org/10.1016/j.ijleo.2022.168854.
[11] R. Ebrahimifard, H. Abdizadeh, M.R. Golobostanfard, Controlling the extremely preferred orientation texturing of sol–gel derived ZnO thin films with sol and heat treatment parameters, J. Sol-Gel Sci. Technol. 93 (2020) 28–35. https://doi.org/10.1007/s10971-019-05157-2.
[12] Y.-S. Kim, W.-P. Tai, S.-J. Shu, Effect of preheating temperature on structural and optical properties of ZnO thin films by sol–gel process, Thin solid films. 491 (2005) 153–160. https://doi.org/10.1016/j.tsf.2005.06.013.
[13] A. Kaya Balta, Ö. Ertek, N. Eker, İ. Okur, MgO and ZnO composite thin films using the spin coating method on microscope glasses, Mater. Sci. Appl. 6 (2015) 40–47. https://doi.org/10.4236/msa.2015.61006.
[14] M. Ayachi, F. Ayad, A. Djelloul, S. Sali, S. Anas, et al., Investigation of structural, morphological, and optical properties of (Ni/Co, Fe/Co, and Fe/Ni) co-doped ZnO thin films prepared by sol-gel spin coating technique, J. Sol-Gel Sci. Technol. 110 (2024) 1–15. https://doi.org/10.1007/s10971-024-06376-y.
[15] I.Y. Bouderbala, A. Guessoum, S. Rabhi, O. Bouhlassa, I.-E. Bouras, Optical band-diagram, Urbach energy tails associated with photoluminescence emission in defected ZnO thin films deposited by sol–gel process dip-coating: effect of precursor concentration, Appl. Phys. A. 130 (2024) 205. https://doi.org/10.1007/s00339-024-07366-1.
[16] G. Demircan, E.F. Gurses, A. Acikgoz, S. Yalcin, B. Aktas, Effects of spin coating parameters on stress, electrical and optical properties of multilayer ZnO thin film prepared by sol–gel, Mol. Cryst. Liq. Cryst. 709 (2020) 61–69. https://doi.org/10.1080/15421406.2020.1816009.
[17] S. Handani, D. Dahlan, S. Arief, Enhanced structural, optical and morphological properties of ZnO thin film using green chemical approach, Vacuum. 179 (2020) 109513. https://doi.org/10.1016/j.vacuum.2020.109513.
[18] B.K. Dejene, T.M. Geletaw, A review of plant-mediated synthesis of zinc oxide nanoparticles for self-cleaning textiles, Res. J. Text. Appar. 28 (2024) 879–892. https://doi.org/10.1108/RJTA-12-2022-0154.
[19] N.S. Rao, M.B. Rao, Structural and optical investigation of ZnO nanopowders synthesized from zinc chloride and zinc nitrate, Am. J. Mater. Sci. 5 (2015) 66–68. https://doi.org/10.5923/j.materials.20150503.02.
[20] K. Nadarajah, C.Y. Chee, C.Y. Tan, Influence of annealing on properties of spray deposited ZnO thin films, J. Nanomater. 2013 (2013) 22–22. https://doi.org/10.1155/2013/146382.
[21] E. Heredia, C. Bojorge, J. Casanova, H. Cánepa, A. Craievich, G. Kellermann, Nanostructured ZnO thin films prepared by sol–gel spin-coating, Appl. Surf. Sci. 317 (2014) 19–25. https://doi.org/10.1016/j.apsusc.2014.08.046.
[22] D. Aryanto, E. Hastuti, M. Taspika, K. Anam, I. Isnaeni, et al., Characteristics and photocatalytic activity of highly c-axis-oriented ZnO thin films, J. Sol-Gel Sci. Technol. 96 (2020) 226–235. https://doi.org/10.1007/s10971-020-05361-5.
[23] L. Znaidi, Sol–gel-deposited ZnO thin films: A review, Mater. Sci. Eng: B. 174 (2010) 18–30. https://doi.org/10.1016/j.mseb.2010.07.001.
[24] G. Swati, S. Mishra, D. Yadav, R. Sharma, D. Dwivedi, et al., High yield synthesis and characterization of aqueous stable zinc oxide nanocrystals using various precursors, J. alloys compd. 571 (2013) 1–5. https://doi.org/10.1016/j.jallcom.2013.03.218.
[25] K.O. Olumurewa, M.A. Eleruja, Photoelectrical and thermal sensing measurement of spin coated ZnO and ZnO-RGO thin film, Phys. B: Cond. Matter. 650 (2023) 414588. https://doi.org/10.1016/j.physb.2022.414588.
[26] F. Zahedi, R. Sabet Dariani, S.M. Rozati, Spray Pyrolysis Deposition of ZnO Thin Films from Zinc Chloride Precursor Solution at Different Substrate Temperatures, Acta Metall. Sin. (Engl. Lett.). 28 (2015) 110–114. https://doi.org/10.1007/s40195-014-0177-5.
[27] S. Youssef, P. Combette, J. Podlecki, R.A. Asmar, A. Foucaran, Structural and optical characterization of ZnO thin films deposited by reactive rf magnetron sputtering, Cryst. Growth Des. 9 (2009) 1088–1094. https://doi.org/10.1021/cg800905e.
[28] J. Quiñones-Galván, I. Sandoval-Jiménez, H. Tototzintle-Huitle, L. Hernández-Hernández, F. de Moure-Flores, et al., Effect of precursor solution and annealing temperature on the physical properties of Sol–Gel-deposited ZnO thin films, Results Phys. 3 (2013) 248–253. https://doi.org/10.1016/j.rinp.2013.11.001.
[29] L. Znaidi, T. Chauveau, A. Tallaire, F. Liu, M. Rahmani, et al., Textured ZnO thin films by sol–gel process: Synthesis and characterizations, Thin Solid Films. 617 (2016) 156–160. https://doi.org/10.1016/j.tsf.2015.12.031.
[30] R. Bekkari, B. Jaber, H. Labrim, M. Ouafi, N. Zayyoun, L. Laânab, Effect of solvents and stabilizer molar ratio on the growth orientation of sol-gel-derived ZnO thin films, Int. J. Photoenergy. 2019 (2019) 3164043. https://doi.org/10.1155/2019/3164043.
[31] T. Ivanova, A. Harizanova, T. Koutzarova, B. Vertruyen, Optical and structural properties of sol–gel derived ZnO: F thin films, AIP Conference Proceedings, AIP Publishing. 2075 (2019) 140005. https://doi.org/10.1063/1.5091320.
[32] H. Hartnagel, Semiconducting transparent thin films, CRC Press. (1995).
[33] M. Khan, K. Bhatti, R. Qindeel, N. Alonizan, H.S. Althobaiti, Characterizations of multilayer ZnO thin films deposited by sol-gel spin coating technique, Results Phys. 7 (2017) 651–655. https://doi.org/10.1016/j.rinp.2016.12.029.
[34] M.P. Gonullu, D.D. Cakil, C. Cetinkaya, Influence of thermal treatment and Fe doping on ZnO films by ultrasonic spray pyrolysis, Thin Solid Films. 793 (2024) 140265. https://doi.org/10.1016/j.tsf.2024.140265.
Cited By
Submitted
2025-01-19
Available online
2025-06-17
How to Cite
Khanali, O., & Nekouee, K. (2025). Physical properties of spin-coated nanocrystalline zinc oxide thin film. Synthesis and Sintering, 5(2), 93-100. https://doi.org/10.53063/synsint.2025.52268
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Copyright (c) 2025 Omid Khanali, Khanali Nekouee
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