Influence of Thermal Annealing on the Band-Gap of TiO2 Thin Films Produced by the Sol-Gel Method

Year 2024, Volume: 5 Issue: 1, 49 - 56, 30.06.2024

İmran Kanmaz , Murat Tomakin , Göksel Aytemiz , Melih Manır , Vagif Nevruzoğlu

https://doi.org/10.53501/rteufemud.1395013

Abstract

In our study, we used the spin coating method to produce TiO2 thin films on quartz glass using a solution with a concentration of 0.5M. After the coating process, the samples were dried in air at 100°C. Subsequently, annealing was carried out at four different temperatures, namely 300°C, 500°C, 700°C, and 900°C, for a duration of 60 minutes. Comprehensive analyzes including Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD) and optical measurements were carried out to investigate the structural and optical properties of the samples. Optical measurements showed that the highest average transmittance values were obtained for samples annealed at 300°C and 500°C, with percentages of 82.33% and 80.25%, respectively. Remarkably, the maximum transmittance of 99.58% was recorded for films annealed at 500°C. Additionally, band-gap calculations were performed using the Tauc method based on optical measurements of samples exposed to different annealing temperatures. According to our results, samples annealed at 300°C, 500°C, 700°C, and 900°C exhibited band-gap values of 3.42eV, 3.40eV, 3.38eV, and 3.29eV, respectively.

Keywords

TiO2 Thin film, sol-gel, band-gap, thermal annealing

Project Number

TUBITAK 121C375

Influence of Thermal Annealing on the Band-Gap of TiO2 Thin Films Produced by the Sol-Gel Method

Abstract

In our study, we employed the spin coating method to produce TiO2 thin films on quartz glass using a solution with a concentration of 0.5M. After the coating process, the samples underwent heat treatment at 100°C in air ambient for drying. Subsequently, annealing was carried out at four different temperatures, namely 300°C, 500°C, 700°C, and 900°C, for a duration of 60 minutes. The produced samples underwent comprehensive analyses, including Scanning Electron Microscopy (SEM), Energy Dispersion Spectroscopy (EDS), X-ray Diffraction (XRD), and optical measurements, to investigate their structural and optical properties. Optical measurements revealed that the highest average transmittance values were obtained for samples annealed at 300°C and 500°C, with percentages of 82.33% and 80.25%, respectively. Remarkably, the maximum transmittance of 99.58% was recorded for films annealed at 500°C. Additionally, band-gap calculations were performed using the Tauc method based on optical measurements of samples exposed to different annealing temperatures. According to our findings, samples annealed at 300°C, 500°C, 700°C, and 900°C exhibited band-gap values of 3.42eV, 3.40eV, 3.38eV, and 3.29eV, respectively.

Keywords

TiO2 Thin film, sol-gel, band-gap, thermal annealing

Supporting Institution

TUBITAK

Project Number

TUBITAK 121C375

References

• Amin, M.S., Hozhabri, N. and Magnusson, R. (2013). Effects of solid phase crystallization by rapid thermal annealing on the optical constants of sputtered amorphous silicon films. Thin Solid Films, 545, 480-484. https://doi.org/10.1016/j.tsf.2013.08.070
• Andronic, L. and Duta, A. (2007). TiO2 thin films for dyes photodegradation. Thin solid films, 515(16), 6294-6297. https://doi.org/10.1016/j.tsf.2006.11.150
• Baishya, K., Ray, J.S., Dutta, P., Das, P.P. and Das, S.K. (2018). Graphene-mediated band gap engineering of WO3 nanoparticle and a relook at Tauc equation for band gap evaluation. Applied Physics A, 124, 1-6. https://doi.org/10.1007/s00339-018-2097-0
• Dolgonos, A., Mason, T.O. and Poeppelmeier, K.R. (2016). Direct optical band gap measurement in polycrystalline semiconductors: A critical look at the Tauc method. Journal of solid state chemistry, 240, 43-48. https://doi.org/10.1016/j.jssc.2016.05.010
• Garzella, C., Comini, E., Tempesti, E., Frigeri, C. and Sberveglieri, G. (2000). TiO2 thin films by a novel sol–gel processing for gas sensor applications. Sensors and Actuators B: Chemical, 68(1-3), 189-196. https://doi.org/10.1016/S0925-4005(00)00428-7
• Gupta, S.K., Singh, J., Anbalagan, K., Kothari, P., Bhatia, R.R., Mishra, P.K., Manjuladevi, V., Gupta, R.K. and Akhtar, J. (2013). Synthesis, phase to phase deposition and characterization of rutile nanocrystalline titanium dioxide (TiO2) thin films. Applied Surface Science, 264, 737-742. https://doi.org/10.1016/j.apsusc.2012.10.113
• Hanabusa, T., Kusaka, K. and Sakata, O. (2004). Residual stress and thermal stress observation in thin copper films. Thin solid films, 459(1-2), 245-248. https://doi.org/10.1016/j.tsf.2003.12.102
• Hasan, M.M., Haseeb, A.S.M.A., Saidur, R. and Masjuki, H.H. (2008). Effects of annealing treatment on optical properties of anatase TiO2 thin films. International Journal of Mechanical and Mechatronics Engineering, 2(4), 410-414. https://doi.org/10.5281/zenodo.1058617
• Hassan, A.T., Hassan E.S. and Abdulmunem, O.M. (2022). Effect of thermal annealing on the structural and optical properties of TiO2 nanostructures. Journal of the Mechanical Behavior of Materials 30(1), 304-308. https://doi.org/10.1515/jmbm-2021-0033
• Kanmaz, İ. and Tomakin, M. (2023). Effect of precursor solution molarity on electrical and optical properties of spin-coated titanium dioxide (TiO2) thin films. MRS Advances. https://doi.org/10.1557/s43580-023-00671-6
• Lu, Z.X., Zhou, L., Zhang, Z.L., Shi, W.L., Xie, Z.X., Xie, H.Y., Pang, D.W. and Shen, P. (2003). Cell damage induced by photocatalysis of TiO2 thin films. Langmuir, 19(21), 8765-8768. https://doi.org/10.1021/la034807r
• Mahmood, A., Ahmed, N., Raza, Q., Khan, T.M., Mehmood, M., Hassan, M. and Mahmood, N. (2010). Effect of thermal annealing on the structural and optical properties of ZnO thin films deposited by the reactive e-beam evaporation technique. Physica Scripta 82(6) 065801. https://doi.org/10.1088/0031-8949/82/06/065801
• Modreanu, M., Sancho-Parramon, J., Durand, O., Servet, B., Stchakovsky, M., Eypert, C., Naudin, C., Knowles, A., Bridou, F. and Ravet, M.F. (2006). Investigation of thermal annealing effects on microstructural and optical properties of HfO2 thin films. Applied surface science 253(1), 328-334. https://doi.org/10.1016/j.apsusc.2006.06.005
• Pawlak, J. and Al-Ani, S. (2019). Inverse logarithmic derivative method for determining the energy gap and the type of electron transitions as an alternative to the Tauc method. Optical Materials 88, 667-673. https://doi.org/10.1016/j.optmat.2018.12.041
• Stevanovic, A. and Yates Jr, J.T (2013). Electron hopping through TiO2 powder: A study by photoluminescence spectroscopy. The Journal of Physical Chemistry C ,117(46), 24189-24195. https://doi.org/10.1021/jp407765r
• Surah, S.S., Vishwakarma, M., Kumar, R., Nain, R., Sirohi, S., Kumari G. (2019). Tuning the electronic band alignment properties of TiO2 nanotubes by boron doping. Results in Physics, 12, 1725-1731. https://doi.org/10.1016/j.rinp.2019.01.081
• Tanemura, S., Miao, L., Wunderlich, W., Tanemura, M., Mori, Y., Toh, S. and Kaneko, K. (2005). Fabrication and characterization of anatase/rutile–TiO2 thin films by magnetron sputtering: A review. Science and Technology of Advanced Materials, 6(1): 11-17. https://doi.org/10.1016/j.stam.2004.06.003
• Vadas, D., Nagy, Z.K., Csontos, I., Marosi, G. and Bocz, K. (2020). Effects of thermal annealing and solvent-induced crystallization on the structure and properties of poly (lactic acid) microfibres produced by high-speed electrospinning. Journal of Thermal Analysis and Calorimetry, 142(2), 581-594. https://doi.org/10.1007/s10973-019-09191-8
• Wen, T., Gao, J., Shen, J. and Zhou, Z. (2001). Preparation and characterization of TiO2 thin films by the sol-gel process. Journal of Materials Science, 36, 5923-5926. https://doi.org/10.1023/A:1012989012840