Optical and Methanol Sensing Properties of Al-doped ZnO Thin Film

Authors

DOI:

https://doi.org/10.37636/recit.v7n4e375

Keywords:

ZnO films, Aluminum doping, Optical transmittance, Bandgap reduction, Electrical conductivity, Gas sensor sensitivity

Abstract

The study investigates the optical and electrical properties of undoped and aluminum (Al)-doped zinc oxide (ZnO) films, focusing on their performance as gas sensors and their potential applications. Optical analysis, conducted using UV-visible spectrophotometry, reveals that 1% Al-doped ZnO films exhibit the highest transmittance of 91%, indicating superior optical clarity and suitability for applications like solar cell electrodes. In contrast, 3% Al-doped ZnO films show significantly lower transmittance due to increased light scattering and photon absorption. The bandgap of ZnO films decreases with higher Al doping concentrations, from 3.3 eV for undoped ZnO to 3.15 eV for 3% Al-doped ZnO, suggesting enhanced electrical conductivity due to reduced bandgap. The extinction coefficient data demonstrate that 2% Al-doped ZnO has the highest extinction coefficient, reflecting improved light absorption and scattering properties. Electrical characterization through I-V curves indicates that 1% Al-doped ZnO films have higher current (121 µA) compared to undoped (431 µA) and higher doping concentrations, attributed to enhanced carrier concentration and mobility. Sensitivity tests show that 2.5% Al-doped ZnO films exhibit the highest sensitivity to methanol vapor, with a significant reduction in resistance compared to 0.5% Al-doped ZnO films. Resistance measurements with varying methanol volumes reveal a rapid decrease upon gas introduction, stabilizing and then increasing as the gas is removed. Sensitivity analysis indicates that 100 µL methanol provides the highest sensitivity (97%) at 60°C, while 2% Al-doped ZnO films show consistent sensitivity at 60 °C and 100 °C, but not at 80 °C.

Downloads

Download data is not yet available.

References

A. B. Djurišić, X. Chen, Y. H. Leung, and A. M. C. Ng, “ZnO nanostructures: growth, properties and applications,” Journal of Materials Chemistry, vol. 22, no. 14, pp. 6526–6535, 2012. https://doi.org/10.1039/C2JM15548F DOI: https://doi.org/10.1039/c2jm15548f

H. Q. Yan, R. R. He, J. Pham, and P. E. I. D. O. N. G. Yang, “Morphogenesis of one‐dimensional ZnO nano‐and microcrystals,” Advanced Materials, vol. 15, no. 5, pp. 402–405, 2003. https://doi.org/10.1002/adma.200390091 DOI: https://doi.org/10.1002/adma.200390091

K. Ellmer and R. Mientus, “Carrier transport in polycrystalline transparent conductive oxides: A comparative study of zinc oxide and indium oxide,” Thin Solid Films, vol. 516, no. 14, pp. 4620–4627, 2008. https://doi.org/10.1016/j.tsf.2007.05.084 DOI: https://doi.org/10.1016/j.tsf.2007.05.084

S. P. Shrestha, R. Ghimire, J. J. Nakarmi, Y. S. Kim, S. Shrestha, C. Y. Park, and J. H. Boo, “Properties of ZnO: Al films prepared by spin coating of aged precursor solution,” Bulletin of the Korean Chemical Society, vol. 31, no. 1, pp. 112–115, 2010.

https://doi.org/10.5012/bkcs.2010.31.01.112 DOI: https://doi.org/10.5012/bkcs.2010.31.01.112

N. Srinatha, P. Raghu, H. M. Mahesh, and B. Angadi, “Spin-coated Al-doped ZnO thin films for optical applications: Structural, micro-structural, optical and luminescence studies,” Journal of Alloys and Compounds, vol. 722, pp. 888–895, 2017. https://doi.org/10.1016/j.jallcom.2017.06.182 DOI: https://doi.org/10.1016/j.jallcom.2017.06.182

Q. Zhu, Y. M. Zhang, J. Zhang, Z. Q. Zhu, and Q. J. Liu, “A new and high response gas sensor for methanol using molecularly imprinted technique,” Sensors and Actuators B: Chemical, vol. 207, pp. 398–403, 2015. https://doi.org/10.1016/j.snb.2014.10.027 DOI: https://doi.org/10.1016/j.snb.2014.10.027

M. Jiao, “Microfabricated gas sensors based on hydrothermally grown 1-D ZnO nanostructures,” Doctoral dissertation, Acta Universitatis Upsaliensis, 2017. https://www.diva-portal.org/smash/record.jsf?pid=diva2%3A1088876&dswid=8134

A. J. Ghazai, E. A. Salman, and Z. A. Jabbar, “Effect of aluminum doping on zinc oxide thin film properties synthesis by spin coating method,” American Scientific Research Journal for Engineering, Technology, and Sciences, vol. 26, no. 3, pp. 202–211, 2016. https://asrjetsjournal.org/index.php/American_Scientific_Journal/article/view/2280

B. A. Anandh, A. S. Ganesh, R. Thangarasu, R. Sakthivel, R. Kannusamy, and K. Tamilselvan, “Structural, morphological and optical properties of aluminium doped ZnO thin film by dip coating method,” Oriental Journal of Chemistry, vol. 34, no. 3, pp. 2-6, 2018. https://doi.org/10.13005/ojc/340356 DOI: https://doi.org/10.13005/ojc/340356

H. Aydın, F. Yakuphanoglu, and C. Aydın, “Al-doped ZnO as a multifunctional nanomaterial: Structural, morphological, optical and low-temperature gas sensing properties,” Journal of Alloys and Compounds, vol. 773, pp. 802–811, 2019. https://doi.org/10.1016/j.jallcom.2018.09.327 DOI: https://doi.org/10.1016/j.jallcom.2018.09.327

L. H. Kathwate, G. Umadevi, P. M. Kulal, P. Nagaraju, D. P. Dubal, A. K. Nanjundan, and V. D. Mote, “Ammonia gas sensing properties of Al doped ZnO thin films,” Sensors and Actuators A: Physical, vol. 313, no. 112193, pp. 3-4, 2020. https://doi.org/10.1016/j.sna.2020.112193 DOI: https://doi.org/10.1016/j.sna.2020.112193

K. C. Dubey, A. Zaidi, and R. R. Awasthi, “Environmentally benign structural, topographic, and sensing properties of pure and Al-doped ZnO thin films,” ACS Omega, vol. 7, no. 33, pp. 28946–28954, 2022. https://pubs.acs.org/doi/full/10.1021/acsomega.2c02440 DOI: https://doi.org/10.1021/acsomega.2c02440

K. Khojier, “Preparation and investigation of Al-doped ZnO thin films as a formaldehyde sensor with extremely low detection limit and considering the effect of RH,” Materials Science in Semiconductor Processing, vol. 121, no. 105283, pp. 1-5, 2021. https://doi.org/10.1016/j.mssp.2020.105283 DOI: https://doi.org/10.1016/j.mssp.2020.105283

S. Gulec, A. B. Arat, S. Islam, and H. I. Akyildiz, “Effect of optical and electronic structure on the photocatalytic activity of Al doped ZnO ALD thin films on glass fibers,” Journal of Photochemistry and Photobiology A: Chemistry, vol. 115915, pp. 1-5, 2024. https://doi.org/10.1016/j.jphotochem.2024.115915 DOI: https://doi.org/10.1016/j.jphotochem.2024.115915

S. Donati, Photodetectors, vol. 1, Prentice Hall PTR, pp. 1–10, 1999. http://www-9.unipv.it/donati/private/Photodetectors/introd.pdf

C. Kittel and P. McEuen, Introduction to Solid State Physics, John Wiley & Sons, 2018. http://metal.elte.hu/~groma/Anyagtudomany/kittel.pdf

D. F. Swinehart, “The Beer-Lambert law,” Journal of Chemical Education, vol. 39, no. 7, pp. 333, 1962. https://pubs.acs.org/doi/pdf/10.1021/ed039p333 DOI: https://doi.org/10.1021/ed039p333

R. R. Ghimire, Y. P. Dahal, K. B. Rai, and S. P. Gupta, “Determination of optical constants and thickness of nanostructured ZnO film by spin coating technique,” Journal of Nepal Physical Society, vol. 7, no. 2, pp. 119–125, 2021. https://doi.org/10.3126/jnphyssoc.v7i2.38632 DOI: https://doi.org/10.3126/jnphyssoc.v7i2.38632

R. B. Reddy and Y. S. R. Kadapa, “Academic credentials,” Doctoral dissertation, Sri Padmavati Mahila Visvavidyalayam, 2011. https://www.ysrafu.ac.in/faculty/CV-Academic.pdf

S. Jantrasee, P. Moontragoon, and S. Pinitsoontorn, “Thermoelectric properties of Al-doped ZnO: Experiment and simulation,” Journal of Semiconductors, vol. 37, no. 9, pp. 092002, 2022. https://doi.org/10.1088/1674-4926/37/9/092002 DOI: https://doi.org/10.1088/1674-4926/37/9/092002

N. Selmane, A. Cheknane, N. Gabouze, N. Maloufi, and M. Aillerie, “Morphological and optical properties study of ZnO/Porous Silicon (PS) nanocomposites prepared by electrodeposition,” Materials Science in Semiconductor Processing, vol. 7, no.01, pp. 17-22, 2024. https://www.researchgate.net/publication/336881877_Morphological_and_Optical_Properties_Study_of_ZnOPorous_Silicon_PS_Nano_composites_Prepared_by_electro-deposition_Technique

M. Adnan, M. Usman, S. Ali, S. Javed, M. Islam, and M. A. Akram, “Aluminum doping effects on interface depletion width of low temperature processed ZnO electron transport layer-based perovskite solar cells,” Frontiers in Chemistry, vol. 9, pp. 1-5, 2022. https://doi.org/10.3389/fchem.2021.795291 DOI: https://doi.org/10.3389/fchem.2021.795291

S. Benramache, Y. Aoun, S. Lakel, H. Mourghade, R. Gacem, and B. Benhaoua, “Effect of annealing temperature on structural, optical and electrical properties of ZnO thin films prepared by sol-gel method,” Journal of Nano- and Electronic Physics, vol. 10, no. 6, pp. 1-3, 2018. https://bibliotekanauki.pl/articles/31342694 DOI: https://doi.org/10.21272/jnep.10(6).06032

Comparisons of sensitivity of undoped, 0.5% Al, 1.5% Al, 2% Al, 2.5% Al-doped ZnO vs Time at 100μl and 60 oC.

Published

2024-11-20

How to Cite

Pandey, S., Marasini, S., & Ghimire, R. R. (2024). Optical and Methanol Sensing Properties of Al-doped ZnO Thin Film. Revista De Ciencias Tecnológicas, 7(4), 1–16. https://doi.org/10.37636/recit.v7n4e375