Abstract
In this work, 2% aluminum-doped zinc oxide (AZO) thin films are deposited on quartz substrates by radiofrequency magnetron sputtering in confocal configuration at room temperature (RT). The effects of various deposition times (20, 40 and 90 min) on microstructure, surface morphology, optical, luminescence and electrical properties are investigated using different characterization techniques. X-ray diffraction measurements reveal that all AZO thin films have a wurtzite hexagonal structure with a more intense preferential growth direction (002). Better crystallinity and larger grains are observed by increasing deposition time (thickness). Atomic force microscopy images show that the morphology and surface roughness depend on deposition time. The results from the measurements by UV–Visible spectrophotometry put into evidence that all the films are transparent with an average transmittance reaching 78% after 90 min of deposition. Moreover, the bandgap energy decreases from 3.57 to 3.38 eV whereas the refractive index increases from 2.26 to 2.30 with increasing deposition time from 20 to 90 min. Room temperature photoluminescence spectra show a decrease in the entire emission by increasing deposition time while a violet emission is observed only for the AZO film grown for 90 min. Hall Effect measurements demonstrate that electrical properties of the AZO films are improved with increasing sputtering time. Indeed, with the increase of deposition time, the Hall mobility increased from 0.92 to 3.30 cm2/V s and the resistivity decreased from 2.36 × 10–3 to 1.48 × 10–3 Ω cm.
Similar content being viewed by others
References
M.M. Momeni, S.M. Mirhoseini, ZnO nanorod films fabricated on zinc foil for photoelectrochemical water splitting. Surf. Eng. 31, 507–512 (2015). https://doi.org/10.1179/1743294414Y.0000000437
M.M. Momeni, Y. Ghayeb, Visible light-driven photoelectrochemical water splitting. J. Appl. Electrochem. 45, 557–566 (2015). https://doi.org/10.1007/s10800-015-0836-x
J. Ghosh, R. Ghosh, P.K. Giri, Tuning the visible photoluminescence in Al doped ZnO thin film and its application in label-free glucose detection. Sens. Actuator B 254, 681–689 (2018). https://doi.org/10.1016/j.snb.2017.07.110
M. Asemi, M. Ahmadi, M. Ghanaatshoar, Preparation of highly conducting Al-doped ZnO target by vacuum heat treatment for thin film solar cell applications. Ceram. Int. 44, 12862–12868 (2018). https://doi.org/10.1016/j.ceramint.2018.04.096
H. Kim, A. Pique, J.S. Horwitz, H. Murata, Z.H. Kafafi, C.M. Gilmorea, D.B. Chrisey, Effect of aluminum doping on zinc oxide thin films grown by pulsed laser deposition for organic light-emitting devices. Thin Solid Films 377, 798–802 (2000). https://doi.org/10.1016/S0040-6090(00)01290-6
T. Minami, Transparent conducting oxide semiconductors for transparent electrodes. Semicond. Sci. Technol. 20, S35–S44 (2005). https://doi.org/10.1088/0268-1242/20/4/004
R.A. Afre, N. Sharma, M. Sharon, Transparent conducting oxide films for various applications: a review. Rev. Adv. Mater. Sci. 53, 79–89 (2018). https://doi.org/10.1515/rams-2018-0006
Y. Lu, S. Wang, M. Yang, X. Xu, Q. Li, Comparative study of AZO and ITO thin film sputtered at different temperatures and their application in Cu2ZnSnS4 solar cells. J. Mater. Sci. 29, 17525–17532 (2018). https://doi.org/10.1007/s10854-018-9853-y
M. Chaves, R. Ramos, E. Martins, E.C. Rangel, N. Cristino da Cruza, S.F. Durrant, J.R.R. Bortoleto, Al-doping and properties of AZO thin films grown at room temperature: sputtering pressure effect. Mater. Res. 22, e20180665 (2019). https://doi.org/10.1590/1980-5373-MR-2018-0665
K. Necib, T. Touam, A. Chelouche, L. Ouarez, D. Djouadi, B. Boudine, Investigation of the effects of thickness on physical properties of AZO sol-gel films for photonic device applications. J. Alloys Compd. 735, 2236–2246 (2018). https://doi.org/10.1016/j.jallcom.2017.11.361
M. Humayan Kabir, M. Mintu Ali, M. Abdul Kaiyum, M.S. Rahman, Effect of annealing temperature on structural morphological and optical properties of spray pyrolized Al-doped ZnO thin films. J. Phys. Commun. 3, 105007 (2019)
S. Saini, P. Mele, T. Oyake, J. Shiomi, J.-P. Niemelä, M. Karppinen, K. Miyazaki, C. Li, T. Kawaharamura, A. Ichinose, Porosity-tuned thermal conductivity in thermoelectric Al-doped ZnO thin films grown by mist-chemical vapor deposition. Thin Solid Films 685, 180–185 (2019). https://doi.org/10.1016/j.tsf.2019.06.010
L. Ma, X. Ai, H. Quan, W. Yang, X. Du, Resistivity depends on preferred orientation for transparent conductive thin films. J. Korean Phys. Soc. 74, 806–811 (2019). https://doi.org/10.3938/jkps.74.806
E. Güneri, B. Stadler, Effect of growth temperature on the key properties of aluminum-doped zinc oxide thin films prepared by atomic layer deposition. MRS Commun. 9, 1105–1110 (2019). https://doi.org/10.1557/mrc.2019.82
Y. Xia, P. Wang, S. Shi, M. Zhang, G. He, J. Lv, Z. Sun, Deposition and characterization of AZO thin films on flexible glass substrates using DC magnetron sputtering technique. Ceram. Int. 43, 4536–4544 (2017). https://doi.org/10.1016/j.ceramint.2016.12.106
F. Challali, D. Mendil, T. Touam, T. Chauveau, V. Bockelée, A.G. Sanchez, A. Chelouche, M.-P. Besland, Effect of RF sputtering power and vacuum annealing on the properties of AZO thin films prepared from ceramic target in confocal configuration. Mater. Sci. Semicond. Proc. 118, 105217 (2020). https://doi.org/10.1016/j.mssp.2020.105217
D. Mendil, F. Challali, T. Touam, V. Bockelée, S. Ouhenia, A. Souici, D. Djouadi, A. Chelouche, Preparation of RF sputtered AZO/Cu/AZO multilayer films and the investigation of Cu thickness and substrate effects on their microstructural and optoelectronic properties. J. Alloys Compd. 860, 158470 (2020). https://doi.org/10.1016/j.jallcom.2020.158470
M.M. Momeni, Z. Tahmasebi, Effect of electrodeposition time on morphology and photoelecrochemical performance of bismuth vanadate films. Inorg. Chem. Commun. 125, 108445 (2021). https://doi.org/10.1016/j.inoche.2021.108445
M.M. Momeni, Y. Ghayeb, A. Hallaj, R. Bagheri, Z. Songd, H. Farrokhpour, Effects of platinum photodeposition time on the photoelectrochemical properties of Fe2O3 nanotube electrodes. Mater. Lett. 237, 188–192 (2019). https://doi.org/10.1016/j.matlet.2018.11.089
D. Nečas, P. Klapetek, Gwyddion: open-source software for SPM data analysis. Cent. Eur. J. Phys. 10, 181–188 (2012). https://doi.org/10.2478/s11534-011-0096-2
K.H. Ri, Y. Wang, W.L. Zhou, J.X. Gao, X.J. Wang, J. Yu, The structural properties of Al doped ZnO films depending on the thickness and their effect on the electrical properties. Appl. Surf. Sci. 258, 1283–1289 (2011). https://doi.org/10.1016/j.apsusc.2011.07.022
M.K. Puchert, P.Y. Timbrell, R.N. Lamb, Post-deposition annealing of radio frequency magnetron sputtered ZnO films. J. Vac. Sci. Technol. 14, 2220–2230 (1996). https://doi.org/10.1116/1.580050
B.D. Cullity, Elements of X-Ray Diffractions (Addison-Wesley, Reading, 1978)
J.H. Jou, M.Y. Han, D.J. Cheng, Substrate dependent internal stress in sputtered zinc oxide thin films. J. Appl. Phys. 71, 4333–4336 (1992). https://doi.org/10.1063/1.350815
J.A. Thornton, D.W. Hoffman, Stress-related effects in thin films. Thin Solid Films 171, 5–31 (1989). https://doi.org/10.1016/0040-6090(89)90030-8
J.I. Langford, A.J.C. Wilson, Scherrer after sixty years: a survey and some new results in the determination of crystallite size. J. Appl. Cryst. 11, 102–113 (1978). https://doi.org/10.1107/S0021889878012844
A. Chelouche, T. Touam, M. Tazerout, F. Boudjouan, D. Djouadi, A. Doghmane, Effect of Li codoping on highly oriented sol-gel Ce-doped ZnO thin films properties. J. Lumin. 181, 331–336 (2017). https://doi.org/10.1016/j.jlumin.2017.04.047
F. Wang, M.Z. Wu, Y.Y. Wang, Y.M. Yu, X.M. Wu, L.J. Zhuge, Influence of thickness and annealing temperature on the electrical, optical and structural properties of AZO thin films. Vacuum 89, 127–131 (2013). https://doi.org/10.1016/j.vacuum.2012.02.040
S.U. Lee, B. Hong, J.-H. Boo, Structural, electrical, and optical properties of SnO2: Sb films prepared on flexible substrate at room temperature. Jpn. J. Appl. Phys. 50, 01AB10 (2011). https://doi.org/10.1143/JJAP.50.01AB10
G.A. Kumar, M.V.R. Reddy, K.N. Reddy, Structural, optical and electrical characteristics of nanostructured ZnO thin films with various thicknesses deposited by RF magnetron sputtering. Res. J. Phys. Sci. 1, 17–23 (2013)
Q. You, H. Cai, Z. Hu, P. Liang, S. Prucnal, S. Zhou, J. Sun, N. Xu, J. Wu, Blue shift in absorption edge and widening of band gap of ZnO by Al doping and Al–N co-doping. J. Alloys Compd. 644, 528–533 (2015). https://doi.org/10.1016/j.jallcom.2015.05.060
L.W. Wang, F. Wu, D.X. Tian, W.J. Li, L. Fang, C.Y. Kong, M. Zhou, Effects of Na content on structural and optical properties of Na-doped ZnO thin films prepared by sol–gel method. J. Alloys. Compd. 623, 367–373 (2015). https://doi.org/10.1016/j.jallcom.2014.11.055
J. Tauc, Optical properties and electronic structure of amorphous Ge and Si. Mater. Res. Bull. 3, 37–46 (1968). https://doi.org/10.1016/0025-5408(68)90023-8
T. Touam, M. Atoui, I. Hadjoub, A. Chelouche, B. Boudine, A. Fischer, A. Boudrioua, A. Doghmane, Effects of dip-coating speed and annealing temperature on structural, morphological and optical properties of sol-gel nano-structured TiO2 thin films. Eur. Phys. J. Appl. Phys. 67, 30302 (2014). https://doi.org/10.1051/epjap/2014140228
C.A. Parker, J.C. Roberts, S.M. Bedair, M.J. Reed, S.X. Liu, N.A. El-Masry, L.H. Robins, Optical band gap dependence on composition and thickness of InxGa1-xN (0≪ x ≪ 0.25) grown on GaN. Appl. Phys. Lett. 75, 2566–2568 (1999). https://doi.org/10.1063/1.125079
Y.-H. Sun, H.-L. Wang, J. Chen, L. Fang, L. Wang, tructural and optoelectronic properties of AZO thin films prepared by RF magnetron sputtering at room temperature. Trans. Nonferr. Met. Soc. China 26, 1655–1662 (2016). https://doi.org/10.1016/S1003-6326(16)64275-9
M.A. Mahadik, Y.M. Hunge, S.S. Shinde, K.Y. Rajpure, C.H. Bhosale, Semiconducting properties of aluminum-doped ZnO thin films grown by spray pyrolysis technique. J. Semicond. 36, 033002 (2015). https://doi.org/10.1088/1674-4926/36/3/033002
L. Liu, Z. Mei, A. Tang, A. Azarov, A. Kuznetsov, Q.-K. Xue, X. Du, Oxygen vacancies: the origin of n-type conductivity in ZnO. Phys. Rev. B 93, 235305 (2016). https://doi.org/10.1103/PhysRevB.93.235305
E. Burstein, Anomalous optical absorption limit in InSb. Phys. Rev. 93, 632–633 (1954). https://doi.org/10.1103/PhysRev.93.632
T. Ganesh, K. Perumal, R. Kumar, N. Bhaskar, Effect of thickness on micro-structural and optical properties of Al-doped ZnO films prepared by sol-gel spin coating. NHC 17, 171–178 (2017)
A. Samavati, H. Nur, A.F. Ismail, Z. Othaman, Radio frequency magnetron sputtered ZnO/SiO2/glass thin film: role of ZnO thickness on structural and optical properties. J. Alloy Compd. 671, 170–176 (2016). https://doi.org/10.1016/j.jallcom.2016.02.099
A. Duffy, Chemical bonding in the oxides of the elements: a new appraisal. Solid State Chem. 62, 145–157 (1986). https://doi.org/10.1016/0022-4596(86)90225-2
J.A. Duffy, Optical basicity of titanium (IV) oxide and zirconium (IV) oxide. J. Am. Ceram. Soc. 72, 2012–2013 (1989). https://doi.org/10.1111/j.1151-2916.1989.tb06022.x
V. Dimitrov, S. Sakka, Electronic oxide polarizability and optical basicity of simple oxides I. J. Appl. Phys. 79, 1736–1740 (1996). https://doi.org/10.1063/1.360962
A. Chelouche, T. Touam, K. Necib, L. Ouarez, F. Challali, D. Djouadi, Investigation of the effects of drying process on microstructural and luminescence properties of Al-doped ZnO thin films. J. Lumin. 219, 11689 (2020). https://doi.org/10.1016/j.jlumin.2019.116891
R. Haarindraprasad, U. Hashim, S.C. Gopinath, M. Kashif, P. Veeradasan, S. Balakrishnan, K. Foo, P. Poopalan, Low temperature annealed zinc oxide nanostructured thin film-based transducers: characterization for sensing applications. PLoS ONE 10, e0132755 (2015). https://doi.org/10.1371/journal.pone.0132755
A. Mohanta, J.G. Simmons Jr., G. Shen, S.M. Kim, P. Kung, H.O. Everitt, Al doping in ZnO nanowires enhances ultraviolet emission and suppresses broad defect emission. J. Lumin. 211, 264–270 (2019). https://doi.org/10.1016/j.jlumin.2019.03.049
H.W. Kim, M.A. Kebede, H.S. Kim, Structural, Raman, and photoluminescence characteristics of ZnO nanowires coated with Al-doped ZnO shell layers. Curr. Appl. Phys. 10, 60–63 (2010). https://doi.org/10.1016/j.cap.2009.04.012
D. Mendil, F. Challali, T. Touam, A. Chelouche, A.H. Souici, S. Ouhenia, D. Djouadi, Influence of growth time and substrate type on the microstructure and luminescence properties of ZnO thin films deposited by RF sputtering. J. Lumin. 215, 116631 (2019). https://doi.org/10.1016/j.jlumin.2019.116631
S.K. Mishra, S. Bayan, P. Chakraborty, R.K. Srivastava, Defect-dominated optical emission and enhanced ultraviolet photoconductivity properties of ZnO nanorods synthesized by simple and catalyst-free approach. Appl. Phys. A 115, 1193–1203 (2014). https://doi.org/10.1007/s00339-013-7959-x
H. Rotella, Y. Mazel, S. Brochen, A. Valla, A. Pautrat, C. Licitra, N. Rochat, C. Sabbione, G. Rodriguez, E. Nolot, Role of vacancy defects in Al doped ZnO thin films for optoelectronic devices. J. Phys. D 50, 485106 (2017)
A. Djurišić, Y. Leung, K. Tam, Y. Hsu, L. Ding, W. Ge, Y. Zhong, K. Wong, W. Chan, H. Tam, Defect emissions in ZnO nanostructures. Nanotechnology 18, 09570 (2007). https://doi.org/10.1088/0957-4484/18/9/095702
N. Akin, S.S. Cetin, M. Cakmak, T. Memmedli, S. Ozcelik, Effect of film thickness on properties of aluminum doped zinc oxide thin films deposition on polymer substrate. J. Mater. Sci. 24, 5091–5096 (2013). https://doi.org/10.1007/s10854-013-1528-0
Acknowledgements
The authors would like to express their thanks to Prof. A. Doghmane for his careful reading of the manuscript and his corrections of the English language.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Mohamedi, M., Challali, F., Touam, T. et al. AZO thin films grown by confocal RF sputtering: role of deposition time on microstructural, optical, luminescence and electronic properties. J Mater Sci: Mater Electron 32, 25288–25299 (2021). https://doi.org/10.1007/s10854-021-06988-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10854-021-06988-y