Preparation of In2O3 Nanosheets: Effect of Experimental Condition on Morphology and Structure
Main Article Content
Abstract
In this study, In2O3 nanostructures were synthesized by the hydrothermal method through a two-step process, including hydrothermal treatment followed by heat treatment. The hydrothermal conditions, namely temperature and time, were varied to obtain different morphological characteristics of the In2O3 nanostructures. The hydrothermal time and temperature were investigated at three different temperature points and three different time points to determine the optimal conditions at which the In2O3 nanosheets exhibit the most well-defined morphology for gas sensing applications. The hydrothermal condition of 180 °C for 12 h was selected for further investigation of the structural and electrical properties. The morphological and structural characteristics were analyzed using techniques such as field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The results reveal that the nanostructures exhibit diverse morphologies, depending on the hydrothermal conditions, particularly temperature and time. In addition, the gas sensing capabilities of the In2O3 nanosheets toward ammonia were also investigated.
Keywords:
In2O3, nanosheets, hydrothermal, gas sensor.
References
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[4] M. Stankova et al., Sensitivity and Selectivity Improvement of Rf Sputtered WO3 Microhotplate Gas Sensors, Sensors and Actuators B: Chemical, Vol. 113, No. 1, 2006, pp. 241-248, https://doi.org/10.1016/j.snb.2005.02.056.
[5] P. S. Cho, K. W. Kim, J. H. Lee, NO2 Sensing Characteristics of ZnO Nanorods Prepared by Hydrothermal Method, Journal of Electroceramics, 2006, pp. 975-978, https://doi.org/10.1007/s10832-006-8146-7.
[6] J. A. Spencer, A. L. Mock, A. G. Jacobs, M. Schubert, Y. Zhang, M. J. Tadjer, A Review of Band Structure and Material Properties of Transparent Conducting And Semiconducting Oxides: Ga2O3, Al2O3, In2O3, ZnO, SnO2, CdO, NiO, CuO, and Sc2O3, Applied Physics Reviews, Vol. 9, No. 1, 2022, https://doi.org/10.1063/5.0078037.
[7] M. Bao et al., Plate-like p-n Heterogeneous NiO/WO3 Nanocomposites for High Performance Room Temperature NO2 Sensors, Nanoscale, Vol. 6, No. 8, 2014, pp. 4063-4066, https://doi.org/10.1039/c3nr05268k.
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[9] T. Wagner et al., UV Light-enhanced NO2 Sensing by Mesoporous In2O3: Interpretation of Results by a New Sensing Model, Sensors and Actuators B: Chemical, Vol. 187, 2013, pp. 488-494, https://doi.org/10.1016/j.snb.2013.02.025.
[10] B. Shanmuga Priya, M. Shanthi, C. Manoharan, M. Bououdina, Hydrothermal Synthesis of Ga-doped In2O3 Nanostructure and its Structural, Optical and Photocatalytic Properties, Materials Science in Semiconductor Processing, Vol. 71, 2017, pp. 357-365, https://doi.org/10.1016/j.mssp.2017.08.025.
[11] L. Gao, Z. Cheng, Q. Xiang, Y. Zhang, J. Xu, Porous Corundum-type In2O3 Nanosheets: Synthesis and NO2 Sensing Properties, Sensors and Actuators B: Chemical, Vol. 208, 2015, pp. 436-443, https://doi.org/10.1016/j.snb.2014.11.053.
[12] E. Li, Z. Cheng, J. Xu, Q. Pan, W. Yu, W. Y. Chu, Indium Oxide with Novel Morphology: Synthesis and Application in C2H5OH Gas Sensing, Crystal Growth & Design, vol. 9, no. 5, 2009, pp. 2146-2151, https://doi.org/10.1021/CG8007238.
[13] Q. Li, N. Huang, Y. Cui, J. Lin, C. Zhao, L. Ding, Synthesis Of Porous Rod-like In2O3 Nanomaterials and its Selective Detection of NO at Room Temperature, Journal of Alloys and Compounds, Vol. 902, 2022, pp. 163632, https://doi.org/ 10.1016/j.jallcom.2022.163632.
[14] X. Wang et al., High Response Gas Sensors for Formaldehyde Based on Er-doped In2O3 Nanotubes, Journal of Materials Science & Technology, Vol. 31, No. 12, 2015, pp. 1175-1180, https://doi.org/10.1016/j.jmst.2015.11.002.
[15] J. N. O. A. Darko et al., Metal-organic Frameworks-derived In2O3/ZnO Porous Hollow Nanocages for Highly Sensitive H2S Gas Sensor, Chemosphere, Vol. 314, 2023, pp. 137670, https://doi.org/10.1016/j.chemosphere.2022.137670.
[16] J. K. Ko, I. H. Park, K. Hong, K. C. Kwon, Recent Advances in Chemoresistive Gas Sensors Using Two-Dimensional Materials, Multidisciplinary Digital Publishing Institute (MDPI), 2024, https://doi.org/10.3390/nano14171397.
[17] Z. Yang et al., Improvement of Gas Sensitivity to Ethanol By Hydrothermal Preparation of Dy-doped In2O3, Sensors and Actuators B: Chemical, vol. 405, 2024, pp. 135386, https://doi.org/10.1016/j.snb.2024.135386.
[18] S. B. Patil, M. A. More, D. Y. Patil, F. I. Ezema, G. E. Patil, Studies on a Chemiresistive Gas Sensor Based on Sol-gel Grown Nanocrystalline In2O3 Thin Film for Fast Carbon Monoxide Detection, Materials Letters,
Vol. 382, 2025, pp. 137882, https://doi.org/10.1016/j.matlet.2024.137882.
[19] Y. Che, G. Feng, T. Sun, J. Xiao, W. Guo, C. Song, Excellent Gas-Sensitive Properties Towards Acetone of In2O3 Nanowires Prepared by Electrospinning, Colloids and Interface Science Communications, Vol. 45, 2021, https://doi.org/10.1016/j.colcom.2021.100508.
[20] A. Vomiero et al., Sequential Physical Vapor Deposition and Chemical Vapor Deposition for the Growth of In2O3–Sno2 Radial and Longitudinal Heterojunctions, Applied Surface Science, Vol. 323, 2014, pp. 59-64, https://doi.org/10.1016/j.apsusc.2014.07.177.
[21] D. H. Yen, L. T. N. Phu, D. T. T. Le, Synthesis of Tungsten Oxide Nanofibers Using Electrospinning Towards Gas Sensor Application, VNU Journal of Science: Mathematics-Physics, Vol. 41, No. 2, 2025, pp. 84-91, https://doi.org/10.25073/2588-1124/vnumap.4993.
[22] D. Kotsikau, M. Ivanovskaya, Influence of Structure of Fe2O3-In2O3 Nanocomposites on the Sensitivity of Thin-Film Sensors on their Base, Materials Chemistry and Physics, Vol. 160, 2015, pp. 337-344, https://doi.org/10.1016/j.matchemphys.2015.04.047.