Power-Dependent Evolution of Structure and Optical Properties in Gallium-Doped ZnO Magnetron Sputtering Thin Films: Experimental and DFT + U Exploration
DOI:
https://doi.org/10.15407/ujpe70.9.609Keywords:
ZnO, radiofrequency magnetron sputtering, DFT, morphology, transparency, thin filmsAbstract
The effect of radiofrequency magnetron sputtering power on the morphology and optical properties gallium-doped ZnO (GZO) thin films has been investigated. It is found that the sputtering power increasing leads to a decreasing in the size of clusters on the film surface and the thickness of the crystallite columnar structure. It is shown that the optical bandgap decreasing may be due to the appearance of interstitial defects in the crystal lattice. Despite maintaining, a constant weight ratio of ZnO and Ga in the initial target mixture, an Ga concentration increasing in GZO thin films is observed for higher sputtering powers. The formation mechanism for GZO thin films under increasing magnetron sputtering power is proposed. It is associated with the appearance of Zn and O interstitial inclusions in the ZnO crystal lattice. Density functional theory (DFT) calculations (with Hubbard correction, DFT + U) show that the increased Ga concentration does not cause a narrowing of the optical band gap. Instead, an increase in the Ga content leads to the appearance of additional electronic states in the valence band (–5.0 eV), which is associated with Zn 3d and O 2p hybridization with Ga 4s and Ga 4p states, a Zn 3d and O 2p energy levels position changing due to changes in interatomic distances and bond symmetry, and a redistribution of the electron density around Ga atoms.
References
1. D. Banerjee, J.Y. Lao, D.Z. Wang, J.Y. Huang, Z.F. Ren, D. Steeves, B. Kimball, M. Sennett. Large-quantity freestanding ZnO nanowires. Appl. Phys. Lett. 83, 2061 (2003).
https://doi.org/10.1063/1.1609036
2. K.M. Sandeep, S. Bhat, S.M. Dharmaprakash. Structural, optical, and LED characteristics of ZnO and Al doped ZnO thin films. J. Phys. Chem. Solids 104, 36 (2017).
https://doi.org/10.1016/j.jpcs.2017.01.003
3. N. Mursal, N. Irhamni, N. Bukhari, Z. Jalil. Structural and optical properties of zinc oxide (ZnO) based thin films deposited by sol-gel spin coating method. J. Phys. Conf. Ser. 1116, 032020 (2018).
https://doi.org/10.1088/1742-6596/1116/3/032020
4. C. Agashe, O. Kluth, G. Sch¨ope, H. Siekmann, J. H¨upkes, B. Rech. Optimization of the electrical properties of magnetron sputtered aluminum-doped zinc oxide films for opto-electronic applications. Thin Solid Films 442, 167 (2003).
https://doi.org/10.1016/S0040-6090(03)00966-0
5. M. Dvorak, S.-H. Wei, Z. Wu. Origin of the variation of exciton binding energy in semiconductors. Phys. Rev. Lett. 110, 016402 (2013).
https://doi.org/10.1103/PhysRevLett.110.016402
6. D.G. Thomas. The exciton spectrum of zinc oxide. J. Phys. Chem. Solids 15, 86 (1960).
https://doi.org/10.1016/0022-3697(60)90104-9
7. P. Mitra, A.P. Chatterjee, H.S. Maiti. ZnO thin film sensor. Mater. Lett. 35, 33 (1998).
https://doi.org/10.1016/S0167-577X(97)00215-2
8. A. Tubtimtae, M.-W. Lee. ZnO nanorods on undoped and indium-doped ZnO thin films as a TCO layer on nonconductive glass for dye-sensitized solar cells. Superlattices Microst. 52, 987 (2012).
https://doi.org/10.1016/j.spmi.2012.08.002
9. V. Polewczyk, R.M. Maffei, G. Vinai, M. Cicero, S. Prato, P. Capaldo, S.D. Zilio, A. Bona, G. Paolicelli, A. Mescola, S. D'Addato, P. Torelli, S. Benedetti. ZnO thin films growth optimization for piezoelectric application. Sensors 21, 6114 (2021).
https://doi.org/10.3390/s21186114
10. C. Qiu, Y. Wu, J. Song, W. Wang, Z. Li. Efficient planar perovskite solar cells with zno electron transport layer. Coatings 12, 1981 (2022).
https://doi.org/10.3390/coatings12121981
11. D.C. Tiwari, S.K. Dwivedi, P. Dipak, T. Chandel, R. Sharma. Sol-gel derived ZnO as an electron transport layer (ETL) for inverted organic solar cells. In: AIP Conference Proceedings, Provo, Utah, USA, July 16-21, 2017, p. 060024-1.
https://doi.org/10.1063/1.4980429
12. ¨U. ¨Ozg¨ur, Ya. I. Alivov, C. Liu, A. Teke, M.A. Reshchikov, S. Do˘gan, V. Avrutin, S.-j. Cho, H. Morko¸c. A comprehensive review of ZnO materials and devices. J. Appl. Phys. 98, 041301 (2005).
https://doi.org/10.1063/1.1992666
13. A. Kolodziejczak-Radzimska T. Jesionowski. Zinc OxideFrom Synthesis to Application: A review. Materials 7, 2833 (2014).
https://doi.org/10.3390/ma7042833
14. Y.J. Kim, H.S. Lee, J.-S. Noh. Transient behaviors of ZnO thin films on a transparent, flexible polyethylene terephthalate substrate. Thin Solid Films 603, 160 (2016).
https://doi.org/10.1016/j.tsf.2016.02.012
15. P.-H. Lei, H.-M. Wu, C.-M. Hsu. Zinc oxide (ZnO) grown on flexible substrate using dual-plasma-enhanced metalorganic vapor deposition (DPEMOCVD). Surf. Coat. Tech. 206, 3258 (2012).
https://doi.org/10.1016/j.surfcoat.2012.01.023
16. K. Ellmer, R. Mientus. Carrier transport in polycrystalline transparent conductive oxides: A comparative study of zinc oxide and indium oxide. Thin Solid Films. 516, 4620 (2008).
https://doi.org/10.1007/978-3-540-73612-7
17. L.C. Nehru, M. Umadevi, C. Sanjeeviraja. Studies on structural, optical and electrical properties of ZnO thin films prepared by the spray pyrolysis method. Int. J. Mater. Eng. 2, 12 (2012).
https://doi.org/10.5923/j.ijme.20120201.03
18. N. Mursal, N. Irhamni, N. Bukhari, Z. Jalil. Structural and optical properties of zinc oxide (ZnO) based thin films deposited by sol-gel spin coating method. J. Phys.: Conf. Ser. 1116, 032020 (2018).
https://doi.org/10.1088/1742-6596/1116/3/032020
19. T.M. Hammad. Effect of annealing on electrical, structural, and optical properties of sol-gel ITO thin films. Phys. Status Solidi (A) Appl. Mater. Sci. 206, 2128 (2009).
https://doi.org/10.1002/pssa.200881781
20. C. Guillen, J. Herrero. Comparison study of ITO thin films deposited by sputtering at room temperature onto polymer and glass substrates. Thin Solid Films 480-481, 129 (2004).
https://doi.org/10.1016/j.tsf.2004.11.040
21. J.H. Kim, K.A. Jeon, G.H. Kim, S.Y. Lee. Electrical, structural, and optical properties of ITO thin films prepared at room temperature by pulsed laser deposition. Appl. Surf. Sci. 252, 4834 (2005).
https://doi.org/10.1016/j.apsusc.2005.07.134
22. X. Liu et al. In-doped ZnO electron transport layer for High-Efficiency ultrathin flexible organic solar cells. Adv. Sci. 11, 2402158 (2024).
https://doi.org/10.1002/advs.202402158
23. A.K. Ambedkar, M. Singh, V. Kumar, V. Kumar, B.P. Singh, A. Kumar, Y.K. Gautam. Structural, optical and thermoelectric properties of Al-doped ZnO thin films prepared by spray pyrolysis. Surf. Interfaces. 19, 100504 (2020).
https://doi.org/10.1016/j.surfin.2020.100504
24. S.D. Ponja, S. Sathasivam, I.P. Parkin, C.J. Carmalt. Highly conductive and transparent gallium doped zinc oxide thin films via chemical vapor deposition. Sci. Rep. 10, 638 (2020).
https://doi.org/10.1038/s41598-020-57532-7
25. G. Bagha, K. Samavati, H. Naffakh-Moosavy, L.F. Matin. Controlling surface morphology of Ag-doped ZnO as a buffer layer by dispersion engineering in planar perovskite solar cells. Sci. Rep. 14, 4617 (2024).
https://doi.org/10.1038/s41598-024-55379-w
26. W.B. Tarique, M.H. Rahaman, S.S. Dipta, A.H. Howlader, A. Uddin. Solution-Processed bilayered ZnO electron transport layer for efficient inverted Non-Fullerene organic solar cells. Nanomanufacturing 4, 81 (2024).
https://doi.org/10.3390/nanomanufacturing4020006
27. V.V. Zaika, N.K.Shvachko, V.H. Kasiyanenko, V.L. Karbivskyy, V.O. Moskaliuk, I.V. Sukhenko, A.P. Soroka. The influence of aluminum on the morphological, optical properties and electronic structure of ZnO thin films. Funct. Mater. 31, 185 (2024).
28. A.I. Kashuba, B. Andriyevsky, H.A. Ilchuk, R.Yu. Petrus, T.S. Malyi, I.V. Semkiv. Optical and dispersion parameters of the al-doped ZnO thin film. J. Nano-Electron. Phys. 13, 04006 (2021).
https://doi.org/10.21272/jnep.13(4).04006
29. P. Nunes, E. Fortunato, P. Tonello, F.B. Fernandes, P. Vilarinho, R. Martins. Effect of different dopant elements on the properties of ZnO thin films. Vacuum 64, 281 (2002).
https://doi.org/10.1016/S0042-207X(01)00322-0
30. D.K. Kim. Characteristics of Ga doped ZnO thin films deposited by RF magnetron sputtering with base pressure. Appl. Sci. Converg. Technl. 28, 13 (2019).
https://doi.org/10.5757/ASCT.2019.28.1.13
31. J. Hu, R.G. Gordon. Textured aluminum-doped zinc oxide thin films from atmospheric pressure chemical-vapor deposition. J. Appl. Phys. 71, 880 (1992).
https://doi.org/10.1063/1.351309
32. J.N. Hasnidawani, H.N. Azlina, H. Norita, N.N. Bonnia, S. Ratim, E.S. Ali. Synthesis of ZnO nanostructures using Sol-Gel method. Procedia Chem. 19, 211 (2016).
https://doi.org/10.1016/j.proche.2016.03.095
33. S.A. Kamaruddin, K.-Y. Chan, H.-K. Yow, M.Z. Sahdan, H. Saim, D. Knipp. Zinc oxide films prepared by sol-gel spin coating technique.Appl. Phys. A 104, 263 (2010).
https://doi.org/10.1007/s00339-010-6121-2
34. M. Krunks, E. Mellikov. Zinc oxide thin films by the spray pyrolysis method. Thin Solid Films 270, 33 (1995).
https://doi.org/10.1016/0040-6090(95)06893-7
35. R.S. Gon¸calves, P. Barrozo, F. Cunha. Optical and structural properties of ZnO thin films grown by magnetron sputtering: Effect of the radio frequency power. Thin Solid Films 616, 265 (2016).
https://doi.org/10.1016/j.tsf.2016.08.040
36. M.K. Khalaf, H.F. Al-Taay, D.S. Ali. Effect of radio frequency magnetron sputtering power on structural and optical properties of Ti6Al4V thin films. Photonic Sens. 7, 163 (2017).
https://doi.org/10.1007/s13320-017-0390-8
37. N. Srinatha, Y.S. No, V.B. Kamble, S. Chakravarty, N. Suriyamurthy, B. Angadi, A.M. Umarji, W.K. Choi. Effect of RF power on the structural, optical and gas sensing properties of RF-sputtered Al doped ZnO thin films. RSC Adv. 6, 9779 (2016).
https://doi.org/10.1039/C5RA22795J
38. X. Yu, J. Ma, F. Ji, Y. Wang, X. Zhang, C. Cheng, H. Ma. Effects of sputtering power on the properties of ZnO : Ga films deposited by r.f. magnetron-sputtering at low temperature. J. Crys. Growth 274, 474 (2004).
https://doi.org/10.1016/j.jcrysgro.2004.10.037
39. P. Giannozzi et al. QUANTUM ESPRESSO: A modular and open-source software project for quantum simulations of materials. J. Condens. Matter Phys. 21, 395502 (2009).
https://doi.org/10.1088/0953-8984/21/39/395502
40. P. Giannozzi et al. Advanced capabilities for materials modelling with Quantum ESPRESSO. J. Condens. Matter Phys. 29, 465901 (2017).
https://doi.org/10.1088/1361-648X/aa8f79
41. P. Giannozzi et al. Quantum ESPRESSO toward the exascale. J. Chem. Phys. 152, 154105 (2020).
https://doi.org/10.1063/5.0005082
42. J.P. Perdew, A. Ruzsinszky, G.I. Csonka, O.A. Vydrov, G.E. Scuseria, L.A. Constantin, X. Zhou, K. Burke. Restoring the density-gradient expansion for exchange in solids and surfaces. Phys. Rev. Lett. 100, 136406 (2008).
https://doi.org/10.1103/PhysRevLett.100.136406
43. S.L. Dudarev, G.A. Botton, S.Y. Savrasov, C.J. Humphreys, A.P. Sutton. Electron-energy-loss spectra and the structural stability of nickel oxide: An LSDA + U study. Phys. Rev. B 57, 1505 (1998).
https://doi.org/10.1103/PhysRevB.57.1505
44. D.A. Leon, C. Elgvin, P.D. Nguyen, Ø. Prytz, F.S. Hage, K. Berland. Unraveling many-body effects in ZnO: Combined study using momentum-resolved electron energy-loss spectroscopy and first-principles calculations. Phys. Rev. B 109, 115153 (2024).
https://doi.org/10.1103/PhysRevB.109.115153
45. L. Dong, R. Jia, B. Xin, B. Peng, Y. Zhang. Effects of oxygen vacancies on the structural and optical properties of β-Ga2O3. Sci. Rep. 7, 40160 (2017).
https://doi.org/10.1038/srep40160
46. W. Gao, Z. Li. ZnO thin films produced by magnetron sputtering. Ceram. Int. 30, 1155 (2004).
https://doi.org/10.1016/j.ceramint.2003.12.197
47. M. Nie, A. Bikowski, K. Ellmer. Microstructure evolution of Al-doped zinc oxide and Sn-doped indium oxide deposited by radio-frequency magnetron sputtering: A comparison. J. Appl. Phys. 117, 155301 (2015).
https://doi.org/10.1063/1.4916725
48. Y. Sato, M. Taketomo, N. Ito, A. Miyamura, Y. Shigesato. Comparative study on early stages of film growth for transparent conductive oxide films deposited by dc magnetron sputtering. Thin Solid Films 516, 4598 (2007).
https://doi.org/10.1016/j.tsf.2007.05.091
49. K. Ellmer. Magnetron sputtering of transparent conductive zinc oxide: Relation between the sputtering parameters and the electronic properties. J. Phys. D: Appl. Phys. 33, R17 (2000).
https://doi.org/10.1088/0022-3727/33/4/201
50. R. Graillot-Vuilecot, T. Anne-Lise, T. Lecas, C. Cachoncinlle, E. Millon, A. Caillard. Hot target magnetron sputtering process: Effect of infrared radiation on the deposition of titanium and titanium oxide thin films. Vacuum 181, 109734 (2020).
https://doi.org/10.1016/j.vacuum.2020.109734
51. NIST-JANAF Thermochemical Tables (4th ed.). Edited by M.W. Jr. Chase (American Institute of Physics, 1998) [ISBN: 978-156-3968-31-0].
52. F. Van Craeynest, W.M.D. Vorst, W. Dekeyser. Interpretation of the yellow colour of heat treated ZnO powder. Phys. Status Solidi B 8, 841 (1965).
https://doi.org/10.1002/pssb.19650080322
53. J. Tauc. Optical properties and electronic structure of amorphous Ge and Si. Mater. Res. Bull. 3, 37 (1968).
https://doi.org/10.1016/0025-5408(68)90023-8
54. J. Tauc, R. Grigorovici, A. Vancu. Optical properties and electronic structure of amorphous Germanium. Phys. Status Solidi B 15, 627 (1966).
https://doi.org/10.1002/pssb.19660150224
55. V. Karbivskyy, N. Kurgan, M. Hantusch, A. Romansky, I. Sukhenko, L. Karbivska. Design of the electronic structure and properties of calcium apatites via isomorphic modification of the cation sublattice, and prospects of their application. J. Appl. Phys. 135, 065102 (2024).
https://doi.org/10.1063/5.0179754
56. G.G.N. Angilella, N.H. March, I.A. Howard, R. Pucci. Pressure dependence of the energy gaps in diamond-type semiconductors, and their III-V analogues such as InSb. J. Phys. Conf. Ser. 121, 032006 (2008).
https://doi.org/10.1088/1742-6596/121/3/032006
57. E. Burstein. Anomalous optical absorption limit in INSB. Phys. Rev. 93, 632 (1954).
https://doi.org/10.1103/PhysRev.93.632
58. T.S. Moss. The interpretation of the properties of indium antimonide. Proc. Phys. Soc. B 67, 775 (1954).
https://doi.org/10.1088/0370-1301/67/10/306
59. K.E. Knutsen, A. Galeckas, A. Zubiaga, F. Tuomisto, G.C. Farlow, B.G. Svensson, A.Yu. Kuznetsov. Zinc vacancy and oxygen interstitial in ZnO revealed by sequential annealing and electron irradiation. Phys. Rev. B 86, 121203 (2012).
https://doi.org/10.1103/PhysRevB.86.121203
60. L. Schmidt-Mende, J.L. MacManus-Driscoll. ZnO - nanostructures, defects, and devices. Mater. Today 10, 40 (2007).
Downloads
Published
Issue
Section
License
Copyright Agreement
License to Publish the Paper
Kyiv, Ukraine
The corresponding author and the co-authors (hereon referred to as the Author(s)) of the paper being submitted to the Ukrainian Journal of Physics (hereon referred to as the Paper) from one side and the Bogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine, represented by its Director (hereon referred to as the Publisher) from the other side have come to the following Agreement:
1. Subject of the Agreement.
The Author(s) grant(s) the Publisher the free non-exclusive right to use the Paper (of scientific, technical, or any other content) according to the terms and conditions defined by this Agreement.
2. The ways of using the Paper.
2.1. The Author(s) grant(s) the Publisher the right to use the Paper as follows.
2.1.1. To publish the Paper in the Ukrainian Journal of Physics (hereon referred to as the Journal) in original language and translated into English (the copy of the Paper approved by the Author(s) and the Publisher and accepted for publication is a constitutive part of this License Agreement).
2.1.2. To edit, adapt, and correct the Paper by approval of the Author(s).
2.1.3. To translate the Paper in the case when the Paper is written in a language different from that adopted in the Journal.
2.2. If the Author(s) has(ve) an intent to use the Paper in any other way, e.g., to publish the translated version of the Paper (except for the case defined by Section 2.1.3 of this Agreement), to post the full Paper or any its part on the web, to publish the Paper in any other editions, to include the Paper or any its part in other collections, anthologies, encyclopaedias, etc., the Author(s) should get a written permission from the Publisher.
3. License territory.
The Author(s) grant(s) the Publisher the right to use the Paper as regulated by sections 2.1.1–2.1.3 of this Agreement on the territory of Ukraine and to distribute the Paper as indispensable part of the Journal on the territory of Ukraine and other countries by means of subscription, sales, and free transfer to a third party.
4. Duration.
4.1. This Agreement is valid starting from the date of signature and acts for the entire period of the existence of the Journal.
5. Loyalty.
5.1. The Author(s) warrant(s) the Publisher that:
– he/she is the true author (co-author) of the Paper;
– copyright on the Paper was not transferred to any other party;
– the Paper has never been published before and will not be published in any other media before it is published by the Publisher (see also section 2.2);
– the Author(s) do(es) not violate any intellectual property right of other parties. If the Paper includes some materials of other parties, except for citations whose length is regulated by the scientific, informational, or critical character of the Paper, the use of such materials is in compliance with the regulations of the international law and the law of Ukraine.
6. Requisites and signatures of the Parties.
Publisher: Bogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine.
Address: Ukraine, Kyiv, Metrolohichna Str. 14-b.
Author: Electronic signature on behalf and with endorsement of all co-authors.
.png){kind=small}
