Structural, morphological, optical and electrical properties of Al-doped ZnO thin films prepared by Sol-Gel spin coating
DOI:
https://doi.org/10.31349/RevMexFis.72.061005Keywords:
Al doped ZnO, sol gel, spin coating, structural properties, optical transparencyAbstract
Undoped and aluminum-doped ZnO (AZO) thin films were prepared by the sol-gel method using spin coating. The films exhibited the characteristic wurtzite crystal structure of ZnO with a preferential orientation along the c-axis. Surface and cross-sectional morphologies were analyzed by scanning electron microscopy (SEM), revealing noticeable differences between the doped and undoped films. The optical transmittance was approximately 77% in the 450-750 nm range. Electrical resistivity decreased from 1.9×105 Ω·cm (ZnO) to 1.0×102 Ω·cm (AZO). These results suggest that low-level Al doping enhances the electrical properties while preserving good optical transparency in AZO thin films. Furthermore, the results highlight the correlation between structural, optical, and electrical properties in ZnO and AZO thin films.
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References
Z. Wang et al., Vacancy cluster in ZnO films grown by pulsed laser deposition, Sci. Rep. 9 (2019) 3534 DOI: https://doi.org/10.1038/s41598-019-40029-3
T. Ivanova et al., Sol-Gel synthesis of ZnO:Li thin films: Impact of annealing on structural and optical properties, Crystals 14 (2023) 6 DOI: https://doi.org/10.3390/cryst14010006
S. Mridha, D. Basak, Aluminium doped ZnO films: electrical, optical and photoresponse studies, J. Phys. D: Appl. Phys. 40 (2007) 6902 DOI: https://doi.org/10.1088/0022-3727/40/22/008
K. M. Mohamed et al., Recent advances in ZnO-based nanostructures for photocatalytic degradation, Crystals 13 (2023) 329 DOI: https://doi.org/10.3390/cryst13020329
S. Ghosh et al., Piezoelectric-based bioactive ZnO-cellulose acetate mats, Front. Immunol. 14 (2023) 1245343 DOI: https://doi.org/10.3389/fimmu.2023.1245343
A. Wibowo et al., ZnO nanostructured materials for solar cell applications, RSC Adv. 10 (2020) 42838 DOI: https://doi.org/10.1039/D0RA07689A
N. Zhang et al., ZnO transparent conductive films with upconversion function, Mater. Sci. Eng. B 325 (2026) 119076 DOI: https://doi.org/10.1016/j.mseb.2025.119076
Y. C. Kao et al., Performance comparison of III-V multijunction solar cells, Sci. Rep. 9 (2019) 4308
D. Zhao et al., n-Type conducting P-doped ZnO thin films, RSC Adv. 10 (2020) 34527 DOI: https://doi.org/10.1039/D0RA05667G
I. Jellal et al., Comparative study of Al- and Nidoped ZnO films, Opt. Quantum Electron. 55 (2023) 620 DOI: https://doi.org/10.1007/s11082-023-04798-6
L. E. Morinigo et al., Aluminum-doped zinc oxide thin films, Mater. Sci. Eng. B 318 (2025) 118279 DOI: https://doi.org/10.1016/j.mseb.2025.118279
Q. A. Drmosh et al., Cu-doped ZnO thin films by PLD, Appl. Surf. Sci. 270 (2013) 104 DOI: https://doi.org/10.1016/j.apsusc.2012.12.126
N. K. Temizer et al., Ferromagnetism in Al-doped ZnO films, AIP Adv. 14 (2024) 105331 DOI: https://doi.org/10.1063/5.0224007
L. He et al., Topological insulator thin films, Phys. Status Solidi RRL 7 (2013) 50 DOI: https://doi.org/10.1002/pssr.201307003
Y. Shen et al., Blue light emission from ZnO/GaN heterojunction, Curr. Appl. Phys. 14 (2014) 345 DOI: https://doi.org/10.1016/j.cap.2013.12.011
W. Yang et al., Al-doped ZnO films by sputtering, Appl. Surf. Sci. 255 (2009) 5669 DOI: https://doi.org/10.1016/j.apsusc.2008.12.021
Y. Ammaih et al., ZnO:Al thin films properties, Opt. Quantum Electron. 46 (2014) 229 DOI: https://doi.org/10.1007/s11082-013-9757-2
X. Zi-qiang et al., Al-doping effects in ZnO films, Mater. Sci. Semicond. Process. 9 (2006) 132 DOI: https://doi.org/10.1016/j.mssp.2006.01.082
H. M. Hussein, Cu-doped ZnO thin films, Results Opt. 13 (2023) 100543 DOI: https://doi.org/10.1016/j.rio.2023.100543
H. Stroescu et al., Sol-gel AZO thin films, Materials 16 (2023) 3329 DOI: https://doi.org/10.3390/ma16093329
K. D. A. Kumar et al., Sol-gel Al-doped ZnO films, Appl. Phys. A 123 (2017) 801 DOI: https://doi.org/10.1007/s00339-017-1426-z
K. Baba et al., ZnO films by spray plasma, Thin Solid Films 595 (2015) 129 DOI: https://doi.org/10.1016/j.tsf.2015.10.072
D. Zhang et al., Al-doped ZnO films, J. Am. Ceram. Soc. 93 (2010) 3291. DOI: https://doi.org/10.1111/j.1551-2916.2010.03847.x
M. S. Nadeem et al., Co, Ni co-doped ZnO nanorods, Opt. Mater. 111 (2021) 110606 DOI: https://doi.org/10.1016/j.optmat.2020.110606
A. A. Aboud et al., Doping effects on ZnO thin films, RSC Adv. 9 (2019) 7729 DOI: https://doi.org/10.1039/C8RA10599E
B. D. Cullity, S. R. Stock, Elements of X-ray Diffraction, Prentice Hall, Upper Saddle River, NJ (2001)
M. S. Nadeem et al., Sr-doped ZnO thin film, Opt. Mater. 157 (2024) 116106 DOI: https://doi.org/10.1016/j.optmat.2024.116106
A. Kumar, M. I. Ahmad, Role of defects in Al-doped ZnO films, J. Mater. Sci. 57 (2022) 7877 DOI: https://doi.org/10.1007/s10853-022-07136-5
M. Khiari et al., ZnO thin films by liquid deposition, Coatings 12 (2022) 65 DOI: https://doi.org/10.3390/coatings12010065
R. G. B. Madera et al., ZnO thin films using sintered targets, Physica B 698 (2025) 416733 DOI: https://doi.org/10.1016/j.physb.2024.416733
M.W. Zhu et al., Sol-gel ZnO films, J. Non-Cryst. Solids 354 (2008) 2416 DOI: https://doi.org/10.1016/j.jnoncrysol.2007.02.087
Y. Demirhan, Anti-reflective coatings, Opt. Quantum Electron. 58 (2026) 75 DOI: https://doi.org/10.1007/s11082-026-08675-w
W. Li et al., Anti-reflection ZnO coatings, Mater. Lett. 243 (2019) 108 DOI: https://doi.org/10.1016/j.matlet.2019.01.158
Y. Li et al., Superhydrophobic coatings, Chem. Commun. (2009) 2730 DOI: https://doi.org/10.1039/b900804g
S. Salam et al., Sol-gel ZnO films, Thin Solid Films 529 (2013) 242 DOI: https://doi.org/10.1016/j.tsf.2012.10.079
H. Zhou et al., Al-doped ZnO films, Thin Solid Films 515 (2007) 6909 DOI: https://doi.org/10.1016/j.tsf.2007.01.041
K. Shalimova, Physics of Semiconductors, Mir, Moscow (1975)
G. L. Kabongo et al., Holmium-doped ZnO, Nanomaterials 11 (2021) 2611 DOI: https://doi.org/10.3390/nano11102611
N. Al-Khalli et al., ZnO thin films properties, Mater. Trans. 62 (2021) 915 DOI: https://doi.org/10.2320/matertrans.MT-M2020350
J. Tauc, Optical properties of amorphous semiconductors, Mater. Res. Bull. 3 (1968) 37 DOI: https://doi.org/10.1016/0025-5408(68)90023-8
A. López-Suárez et al., Mn-doped ZnO films, J. Mater. Sci.: Mater. Electron. 31 (2020 DOI: https://doi.org/10.1007/s10854-019-02830-8
M. R. Islam, M. G. Azam, Mg-doped ZnO films, Surf. Eng. 37 (2021) 775 DOI: https://doi.org/10.1080/02670844.2020.1801143
F. Urbach, Absorption edge in solids, Phys. Rev. 92 (1953) 1324 DOI: https://doi.org/10.1103/PhysRev.92.1324
R. C. Rai, Urbach tails in ZnO, J. Appl. Phys. 113 (2013) 153508 DOI: https://doi.org/10.1063/1.4801900
P. Potera et al., Co-doped ZnO films, Appl. Sci. 13 (2023) 2701 DOI: https://doi.org/10.3390/app13042701
F. M. Smits, Four-point probe method, Bell Syst. Tech. J. 34 (1958) 711 DOI: https://doi.org/10.1002/j.1538-7305.1958.tb03883.x
K. M. Salman et al., Mg-doped ZnO films, Opt. Mater. 158 (2025) 116460 DOI: https://doi.org/10.1016/j.optmat.2024.116460
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