A Study on Effect of Sol Aging Time on Optical Properties of ZnO Thin Films: Spectroscopic Ellipsometry Method

Author(s): Ehsan Motallebi Aghkonbad, Maryam Motallebi Aghgonbad*, Hassan Sedghi

Journal Name: Micro and Nanosystems

Volume 11 , Issue 2 , 2019

Become EABM
Become Reviewer
Call for Editor

Graphical Abstract:


Background: Due to wide band gap and large excitonic binding energy, being inexpensive, abundance in nature and easy synthesis ZnO is a promising candidate in many applications such as solar cells.

Experimental: In the current work a series of ZnO thin films were deposited on glass substrates using sol-gel method to investigate the change in optical behavior of the film with sol aging time (asprepared, 8, 16, 24 and 32 hours) and the annealing temperature (300ᵒC and 500ᵒC). The optical properties of thin films were explored using spectroscopic ellipsometry method including the real and imaginary part of refractive index, real and imaginary part of dielectric function and band gap energy of the layers in the 300-900 nanometer wavelength range.

Results: It can be deduced from the results that sol aging time and annealing temperature, affect the optical properties of the samples. Using single oscillator energy model of Wemple and Di Domenico parameters such as free charge carrier concentration ratio to effective mass, and plasma frequency, were calculated.

Conclusion: The films prepared using 24 h aged solution, had the highest transmittance and the largest band gap energy.

Keywords: Zinc oxide, spectroscopic ellipsometry, aging time, annealing, refractive index, gap energy.

Toubane, M.; Tala-Ighil, R.; Bensouici, F.; Bououdina, M.; Cai, W.; Liu, S.; Souier, M.; Iratni, A. Structural, optical and photocatalytic properties of ZnO nanorods: Effect of aging time and number of layers. Ceram. Int., 2016, 42, 9673-9685.
Godavarti, U.; Mote, V.D.; Dasari, M. Role of cobalt doping on the electrical conductivity of ZnO nanoparticles. J. Asian Ceramic Soc., 2017, 5(4), 391-396.
Chaitra, U.; Kekuda, D.; Rao, K.M. Effect of annealing temperature on the evolution of structural, microstructural, and optical properties of spin coated ZnO thin films. Ceram. Int., 2017, 43, 7115-7122.
Bhardwaj, V.; Chowdhury, R.; Jayaganthan, R. Nanomechanical and microstructural characterization of sputter deposited ZnO thin films. Appl. Surf. Sci., 2016, 389, 1023-1032.
Kumar, M.; Jeong, H.; Lee, D. Sol-gel derived Hf- and Mg-doped high-performance ZnO thin film transistors. J. Alloys Compd., 2017, 720, 230-238.
Lee, H.; Zhang, X.; Hwang, J.; Park, J. Morphological influence of solution-processed zinc oxide films on electrical characteristics of thin-film transistors. Materials., 2016, 9, 851.
Gençyılmaz, O.; Atay, F.; Akyuz, I. Deposition and ellipsometric characterization of transparent conductive Al-doped ZnO for solar cell application. J. Clean Energ. Technol., 2016, 4, 90-94.
Sandeep, K.M.; Bhat, S.; Dharmaprakash, S.M. Structural, optical, and LED characteristics of ZnO and Al doped ZnO thin films. J. Phys. Chem. Solids, 2017, 104, 36-44.
Musat, V.; Rego, A.M.; Monteiro, R.; Fortunato, E. Microstructure and gas-sensing properties of sol-gel ZnO thin films. Thin Solid Films, 2008, 516, 1512-1515.
Rameshkumar, C.; Subalakshmi, R. Structural, optical and electrical properties of ZnO: Al thin films synthesized by low cost spray pyrolysis for optoelectronic applications. J. Chem. Pharm. Res., 2015, 7, 459-466.
Azzouz, I.; Habba, Y.G.; Capochichi-Gnambodoe, M.; Marty, F.; Vial, J.; Leprince-Wang, Y.; Bourouina, T. Zinc oxide nano-enabled microfluidic reactor for water purification and its applicability to volatile organic compounds. Microsyst. Nanoeng., 2018, 4, 17093.
Gai, M.; Frueh, J.; Kudryavtseva, V.L.; Yashchenok, A.M.; Sukhorukov, G.B. Polylactic acid sealed polyelectrolyte multilayer microchambers for entrapment of salts and small hydrophilic molecules precipitates. ACS Appl. Mater. Interfaces, 2017, 9, 16536-16545.
Uprety, P.; Junda, M.M.; Ghimire, K.; Adhikari, D.; Grice, C.R.; Podraza, N.J. Spectroscopic ellipsometry determination of optical and electrical properties of aluminum doped zinc oxide. Appl. Surf. Sci., 2017, 421, 852-858.
Jain, A.; Johari, M.; Jain, A.; Pandey, P.K.; Agrawa, R. Modification in optical properties of ZnO thin film by annealing. Int. J. Innov. Res. Sci. Eng. Technol., 2013, 2, 3144-3148.
Choi, S.Y.; Choi, K.; Kim, S.J. Rapid thermal annealing effects on the electrical and structural properties of the AZO thin film deposited at a room temperature. Int. J. Adv. Res. Electr. Electr. Instrument. Eng., 2013, 2, 6034-6043.
Juwhari, H.K.; Ikhmayies, S.J.; Lahlouh, B. Room temperature photoluminescence of spray deposited ZnO thin films on glass substrates. Int. J. Hydrogen Energy, 2017, 42, 17741-17747.
Alami, Z.Y.; Salem, M.; Gaidi, M.; Elkhamkhami, J. Effect of Zn concentration on structural and optical proprieties of ZnO thin films deposited by spray pyrolysis. Adv. Energ. Int. J., 2015, 2, 11-24.
Moreh, A.U.; Momoh, M.; Abdullahi, S.; Shehu, J.S.; Mustapha, M.O.; Martha, N.C. The role of annealing temperature on optical properties of ZnO thin films prepared by spray pyrolysis techniques. J. Multidiscip. Eng. Sci. Technol., 2015, 2, 2247-2251.
Saji, K.J.; Manoj, R.; Ajimsha, R.S.; Jayaraj, M.K. Growth of zinc oxide thin films for optoelectronic application by pulsed laser deposition. In: Advances in Thin-Film Coatings for Optical Applications III, International Society for Optics and Photonics. 2006, 6286, 62860D.
Vallejos, S.; Maggio, F.D.; Shujah, T.; Blackman, C. Chemical vapour deposition of gas sensitive metal oxides. Chemosensors., 2016, 4, 1-18.
Periasamy, C.; Prakash, R.; Chakrabarti, P. Effect of post annealing on structural and optical properties of ZnO thin films deposited by vacuum coating technique. J. Mater. Sci. Mater. Electron., 2009, 21, 309-315.
Saleem, M.; Fang, L.; Ruan, H.B.; Wu, F.; Huang, Q.L.; Xu, C.L.; Kong, C.Y. Effect of zinc acetate concentration on the structural and optical properties of ZnO thin films deposited by sol-gel method. Int. J. Phys. Sci., 2012, 7, 2971-2979.
Hussein, H.F.; Shabeeb, G.M.; Hashim, S.S. Preparation ZnO thin film by using sol-gel-processed and determination of thickness and study optical properties. J. Mater. Environ. Sci., 2011, 2, 423-426.
Coskun, C.; Guney, H.; Gur, E.; Tuzemen, S. Effective annealing of ZnO thin films grown by electrochemical deposition technique. Turk. J. Phys., 2009, 33, 49-56.
Ibrahim, N.B.; Al-Shomar, S.M.; Ahmad, S.H. Effect of aging time on the optical, structural and photoluminescence properties of nanocrystalline ZnO films prepared by a sol-gel method. Appl. Surf. Sci., 2013, 283, 599-602.
Nagayasamy, N.; Gandhimathination, S.; Veerasamy, V. The effect of ZnO thin film and its structural and optical properties prepared by sol-gel spin coating method. Open J. Metal., 2013, 3, 8-11.
Shivaraj, B.W.; Murthy, H.N.; Krishna, M.; Sharma, S.C. Investigation of influence of spin coating parameters on the morphology of ZnO thin films by Taguchi method. Int. J. Thin Film Sci. Tec., 2013, 2, 143-154.
Ajadi, D.A.; Agboola, S.M.; Adedokun, O. Effect of spin coating speed on some optical properties of ZnO thin films. J. Mater. Sci. Chem. Eng., 2016, 4, 1-6.
Li, Y.; Xu, L.; Li, X.; Shen, X.; Wang, A. Effect of aging time of ZnO sol on the structural and optical properties of ZnO thin films prepared by sol-gel method. Appl. Surf. Sci., 2010, 256, 4543-4547.
Synowicki, R. Transparent substrates: How to suppress reflections from the back surface 2010.Avaiable from. https://www.jaw japan.com/document/public/000/General_01_Transparent%20 Subs- trates%20Suppressing%20Backside%20Reflections.pdf
Frueh, J.; Reiter, G.; Moehwald, H.; He, Q.; Krastev, R. Novel controllable auxetic effect of linearly elongated supported polyelectrolyte multilayer with amorphous structure. Phys. Chem. Chem. Phys., 2013, 15, 483-488.
Fricke, L.; Bontgen, T.; Lorbeer, J.; Bundesmann, C.; Grund, R.S.; Grundmann, M. An extended Drude model for the in-situ spectroscopic ellipsometry analysis of ZnO thin layers and surface modifications. Thin Solid Films, 2014, 571, 437-441.
Galvan, A.M.; Cruz, C.T.; Lee, J.; Bhattacharyya, D.; Metson, J.; Evans, P.J.; Pal, U. Effect of metal-ion doping on the optical properties of nanocrystalline ZnO thin films. J. Appl. Phys., 2006, 99014306
Motallebi Aghgonbad, M.; Sedghi, H. Spectroscopic ellipsometry studies on zinc oxide thin films deposited by sol-gel method with various precursor concentrations. Surf. Rev. Lett., 2018, 26(3)1850158
Srinatha, N.; Raghu, P.; Mahesh, H.M.; Angadi, B. Spin-coated Al-doped ZnO thin films for optical applications: Structural, micro-structural, optical and luminescence studies. J. Alloys Compd., 2017, 722, 888-895.
Petkova, P.; Nedelchev, L.; Nazarova, D.; Boubaker, K.; Mimouni, R.; Vasilev, P.; Alexieva, G.; Bachvarova, D. Single oscillator model of un-doped and co-doped ZnO thin films. Optik., 2017, 139, 217-221.
Bakry, A. Dispersion and fundamental absorption edge analysis of doped a-Si:H thin films I: p-type. Egypt. J. Solids, 2008, 31, 191-204.
Dalouji, V.; Solaymani, S.; Dejam, L.; Elahi, S.M.; Rezaee, S.; Mehrparvar, D. Gap states of ZnO thin films by new methods: Optical spectroscopy, optical conductivity and optical dispersion energy. Chin. Phys. Lett., 2018, 35027701
Mendez, M.G.; Calle, A.B.; Segura, R.R.; Coello, V. Investigation of the annealing effects on the structural and optoelectronic properties of RF-sputtered ZnO films studied by the Drude–Lorentz model. Appl. Phys., A., 2015, 120, 1375-1382.
Tan, G.L.; Denoyer, L.K.; French, R.H.; Guittet, M.J.; Soyer, M.G. Kramers-Kronig transform for the surface energy loss function. J. Electron Spectrosc. Relat. Phenom., 2004, 142, 97-103.

open access plus

Rights & PermissionsPrintExport Cite as

Article Details

Year: 2019
Page: [100 - 108]
Pages: 9
DOI: 10.2174/1876402911666190313155304

Article Metrics

PDF: 23