Physics / Fizik
Permanent URI for this collectionhttps://hdl.handle.net/11147/6
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Article Citation - WoS: 5Citation - Scopus: 5Comparison of Characteristic Properties of Al, Ga, and In-Doped Zno Thin Films Formed by Sol-Gel Method(Academic Press, 2021) Horzum, Şeyda; Bulduk, Emel; Şener, Deniz; Serin, TülayHerein, we examine the effect of doping with Indium (In), Gallium (Ga), and Aluminum (Al) (group III elements) on the structural, optical, and vibrational properties of ZnO thin films. The characteristic properties of the ZnO films prepared by the sol-gel dip-coating method are explored by utilizing X-ray diffraction, optical spectroscopy, and Raman scattering measurements. XRD analyzes exhibit that the crystallite size reduces upon doping by Ga and Al, while it increases with In, and all films have hexagonal wurtzite structure. Additionally, Raman measurements indicate that the dominant two peaks at around 104 and 445 cm(-1) are related to E(2)(low )and E-2(high) phonon modes of ZnO, respectively. The low-frequency mode (E-2(low)) is affected by dopant atoms, whereas the high-frequency mode (E-2(high)) of the wurtzite phase is not influenced by the dopant. Moreover, E-dop.atom phonon mode appears at low frequencies and the intensity ratio, I(E-dop.atom)/I(E(2)low), decreases as the ionic radius of dopant atoms increases. UV-Vis spectra reveal that the film transparency, optical band gap, Urbach energy, and refraction index can be effectively tuned by dopant atoms.Article Citation - WoS: 50Citation - Scopus: 52Monitoring the Characteristic Properties of Ga-Doped Zno by Raman Spectroscopy and Atomic Scale Calculations(Elsevier, 2019) Horzum, Şeyda; İyikanat, Fadıl; Senger, Ramazan Tuğrul; Çelebi, Cem; Sbeta, Mohamed; Yıldız, Abdullah; Serin, TülayWe experimentally and theoretically study how the structural and vibrational properties of zinc oxide (ZnO) are modified upon Gallium (Ga) doping. The characteristics of Ga-doped ZnO thin films which are synthesized by sol-gel spin coating method on glass substrates are monitored by using X-ray diffraction (XRD) and Raman scattering measurements. For atomic-level understanding of the experimental findings state-of-the-art density functional theory (DFT) based calculations are also performed. DFT calculations reveal that both the substitution and adsorption of Ga atoms in ZnO are energetically possible and substitutional doping in ZnO is the most favourable scenario. XRD measurements show that all the films are in wurtzite structure and the crystallite size of the films decreases with increasing Ga doping. In addition, Raman analysis show that strong vibrational modes at about 100 and 441 cm(-1) are associated with E-2(low) and E-2(high) phonon branches of ZnO, respectively. While the frequency of the E-2(low) mode downshifts with increasing Ga concentration, the E-2(high) phonon mode is not affected by the Ga doping. Furthermore, E-Ga phonon branch, stemming from the substituted Ga atoms, emerges at low frequencies. It is also seen that the Raman intensity of the E-G(a) peak linearly increases with increasing Ga concentration. Experimental results on the vibrational properties are in good agreement with the ab initio phonon calculations. (C) 2018 Elsevier B.V. All rights reserved.