隨著人工智慧（AI）和物聯網（IoT）的發展，對高性能電子產品的需求日益增長，進而增加了難以分解的電子廢物。為了解決這個問題，生物材料被探索用於可持續的設備，但阿拉伯膠在氣體感測中的應用仍然未被充分利用。本研究開發了一種生物模板的阿拉伯膠-氧化鋅（GA/ZnO）氣體感測器，用於二氧化氮（NO₂）檢測。這種生物模板增強了氧化鋅的孔隙率，改善了氣體吸附和靈敏度。
在第三章中，探討了阿拉伯膠在增強表面氧空位的作用，這創造了額外的NO₂吸附位點，進而提高了感測器的靈敏度和選擇性。與現有研究相比，我們的GA/ZnO感測器即使在ppb級濃度下也表現出優異的響應。這強調了阿拉伯膠作為生物模板在增強氣體感測中的潛力，並提供了一種環保且高效的空氣質量監測解決方案。NO₂感測性能評估顯示，在僅110 °C的操作溫度下，感測器的響應達到1736.03%，並具有優異的選擇性、12週期的重複性和22天的穩定性。
在第四章中，我們進一步探討GA對材料穩定性與薄膜品質的提升作用，並以此開發出基於NiO/ZnO異質結構的紫外光感測器。ZnO與NiO作為分別具寬能隙的n型與p型半導體，能形成p–n接面，有效提升紫外光的感測效能。GANZ-3元件展現出卓越的響應度（在365 nm波長下達156 A/W）、極低的暗電流與超過10⁴的光/暗電流比。SEM、EDS與XPS分析證實此異質結構具備良好的整合性與富含氧缺陷的環境，進一步強化其光電特性。GA除了促進奈米粒子的分散與薄膜均勻性，也提供了永續且環境友善的元件製備策略，顯示其在高效能紫外光感測器開發中的應用潛力。
本研究促進了環保電子元件的開發，並凸顯出以生物模板提升元件性能的特性。預期這些新穎材料與技術將在推動地球永續發展中扮演重要角色。

With the advancement of artificial intelligence and Internet of Things (IoT) technologies, the demand for high-performance electronic devices has increased significantly, leading to the generation of large amounts of non-degradable electronic waste. To address this issue, researchers have actively explored the application of biomaterials in sustainable electronic devices. However, the use of gum arabic (GA) in gas sensing remains relatively underexplored. In this study, we developed a GA-templated zinc oxide (GA/ZnO) gas sensor for the detection of nitrogen dioxide (NO₂). The use of a biological template enhanced the porosity of ZnO, thereby improving its gas adsorption capacity and sensing sensitivity.
In Chapter 3, we investigate the role of GA in enhancing surface oxygen vacancies, which serve as active sites for NO₂ adsorption, effectively boosting the sensitivity and selectivity of the sensor. Compared to existing studies, our GA/ZnO sensor demonstrates outstanding response performance even at ppb-level concentrations, highlighting the potential of GA as a biotemplate in gas sensing applications. The sensor exhibited a remarkable response of up to 1736.03% at just 110°C, along with excellent selectivity, reproducibility over 12 cycles, and stability over 22 days.
In Chapter 4, we further explore the role of GA in improving material stability and film quality, and based on this, developed a NiO/ZnO heterostructure-based ultraviolet (UV) photodetector. ZnO and NiO, as wide-bandgap n-type and p-type semiconductors respectively, form a p–n junction that effectively enhances UV sensing performance. The GANZ-3 device exhibits an outstanding responsivity of 156 A/W at a wavelength of 365 nm, an ultra-low dark current, and a photo-to-dark current ratio exceeding 10⁴. SEM, EDS, and XPS analyses confirm the good integration of the heterostructure and the presence of oxygen-rich defects, further enhancing its optoelectronic properties. In addition to promoting nanoparticle dispersion and film uniformity, GA offers a sustainable and eco-friendly strategy for device fabrication, demonstrating its potential in the development of high-performance UV photodetector.
This research advances the development of environmentally friendly electronic devices and highlights the performance-enhancing benefits of biotemplating. These novel materials and technologies are expected to play a vital role in promoting sustainable development for the planet.

[1] M. Javaid, A. Haleem, S. Rab, R. P. Singh, and R. Suman, "Sensors for daily life: A review," Sensors International, vol. 2, p. 100121, 2021.
[2] C.-Y. Kao, C.-L. Hsin, C.-W. Huang, S.-Y. Yu, C.-W. Wang, P.-H. Yeh, and W.-W. Wu, "High-yield synthesis of ZnO nanowire arrays and their opto-electrical properties," Nanoscale, vol. 4, no. 5, pp. 1476-1480, 2012.
[3] Y. Juan, S.-J. Chang, H. Hsueh, S. Wang, W. Weng, T. Cheng, and C.-L. Wu, "Effects of humidity and ultraviolet characteristics on β-Ga 2 O 3 nanowire sensor," RSC Advances, vol. 5, no. 103, pp. 84776-84781, 2015.
[4] Q. Li, W. Zeng, and Y. Li, "Metal oxide gas sensors for detecting NO2 in industrial exhaust gas: Recent developments," Sensors and Actuators B: Chemical, vol. 359, p. 131579, 2022.
[5] H.-J. Kim and J.-H. Lee, "Highly sensitive and selective gas sensors using p-type oxide semiconductors: Overview," Sensors and Actuators B: Chemical, vol. 192, pp. 607-627, 2014.
[6] M. A. Franco, P. P. Conti, R. S. Andre, and D. S. Correa, "A review on chemiresistive ZnO gas sensors," Sensors and Actuators Reports, vol. 4, p. 100100, 2022.
[7] R. Li, Q. Zhou, Y. Bi, S. Cao, X. Xia, A. Yang, S. Li, and X. Xiao, "Research progress of flexible capacitive pressure sensor for sensitivity enhancement approaches," Sensors and Actuators A: Physical, vol. 321, p. 112425, 2021.
[8] S. Patel and A. Goyal, "Applications of natural polymer gum arabic: a review," International Journal of Food Properties, vol. 18, no. 5, pp. 986-998, 2015.
[9] C. Verma and M. Quraishi, "Gum Arabic as an environmentally sustainable polymeric anticorrosive material: Recent progresses and future opportunities," International Journal of Biological Macromolecules, vol. 184, pp. 118-134, 2021.
[10] S. Hassan, V. Idrees, H. Ismail, and S. Abdullah, "Prepared by: Supervisor," 2022.
[11] S. Agarwal, S. Kumar, H. Agrawal, M. G. Moinuddin, M. Kumar, S. K. Sharma, and K. Awasthi, "An efficient hydrogen gas sensor based on hierarchical Ag/ZnO hollow microstructures," Sensors and Actuators B: Chemical, vol. 346, p. 130510, 2021/11/01/ 2021.
[12] A. Atilgan, K. Ozel, M. Sbeta, and A. Yildiz, "Engineering the visible light absorption of one-dimensional photonic crystals based on multilayers of Al-doped ZnO (AZO) thin films," Materials Science in Semiconductor Processing, vol. 166, p. 107747, 2023/11/01/ 2023.
[13] Y. Lu, L. Wang, D. Wang, T. Xie, L. Chen, and Y. Lin, "A comparative study on plate-like and flower-like ZnO nanocrystals surface photovoltage property and photocatalytic activity," Materials Chemistry and Physics, vol. 129, no. 1, pp. 281-287, 2011/09/15/ 2011.
[14] X. Geng, D. Lahem, C. Zhang, C.-J. Li, M.-G. Olivier, and M. Debliquy, "Visible light enhanced black NiO sensors for ppb-level NO2 detection at room temperature," Ceramics International, vol. 45, no. 4, pp. 4253-4261, 2019/03/01/ 2019.
[15] H. Gao, L. Zhao, L. Wang, P. Sun, H. Lu, F. Liu, X. Chuai, and G. Lu, "Ultrasensitive and low detection limit of toluene gas sensor based on SnO2-decorated NiO nanostructure," Sensors and Actuators B: Chemical, vol. 255, pp. 3505-3515, 2018/02/01/ 2018.
[16] B. Ezhilmaran, A. Patra, S. Benny, M. Sreelakshmi, V. Akshay, S. V. Bhat, and C. S. Rout, "Recent developments in the photodetector applications of Schottky diodes based on 2D materials," Journal of Materials Chemistry C, vol. 9, no. 19, pp. 6122-6150, 2021.
[17] T. Delipinar, A. Shafique, M. S. Gohar, and M. K. Yapici, "Fabrication and materials integration of flexible humidity sensors for emerging applications," ACS omega, vol. 6, no. 13, pp. 8744-8753, 2021.
[18] S. Dhall, B. R. Mehta, A. K. Tyagi, and K. Sood, "A review on environmental gas sensors: Materials and technologies," Sensors International, vol. 2, p. 100116, 2021/01/01/ 2021.
[19] K. Meng, X. Xiao, W. Wei, G. Chen, A. Nashalian, S. Shen, X. Xiao, and J. Chen, "Wearable pressure sensors for pulse wave monitoring," Advanced Materials, vol. 34, no. 21, p. 2109357, 2022.
[20] A. N. Raja, "Recent development in chitosan-based electrochemical sensors and its sensing application," International Journal of Biological Macromolecules, vol. 164, pp. 4231-4244, 2020.
[21] S. Li, W. Zhou, Y. Hu, C. Huang, Q. Gao, and Y. Chen, "Preparation of graphene-starch composite film and its application in sensor materials," International Journal of Biological Macromolecules, vol. 207, pp. 365-373, 2022.
[22] M. Chao, L. He, M. Gong, N. Li, X. Li, L. Peng, F. Shi, L. Zhang, and P. Wan, "Breathable Ti3C2T x MXene/Protein nanocomposites for ultrasensitive medical pressure sensor with degradability in solvents," ACS nano, vol. 15, no. 6, pp. 9746-9758, 2021.
[23] S. Ray, A. Kumari, M. Sonkar, and P. Kumar, "Polyhydroxyalkanoate-Based Sensors and Their Applications," in Biomaterials-Based Sensors: Recent Advances and Applications: Springer, 2023, pp. 223-243.
[24] T. Sathies, P. Senthil, and C. Prakash, "Application of 3D printed PLA-carbon black conductive polymer composite in solvent sensing," Materials Research Express, vol. 6, no. 11, p. 115349, 2019.
[25] Y. Zhang, Y. Liu, L. Zhou, D. Liu, F. Liu, F. Liu, X. Liang, X. Yan, Y. Gao, and G. Lu, "The role of Ce doping in enhancing sensing performance of ZnO-based gas sensor by adjusting the proportion of oxygen species," Sensors and Actuators B: Chemical, vol. 273, pp. 991-998, 2018/11/10/ 2018.
[26] H. Yu, T. Yang, Z. Wang, Z. Li, Q. Zhao, and M. Zhang, "p-N heterostructural sensor with SnO-SnO2 for fast NO2 sensing response properties at room temperature," Sensors and Actuators B: Chemical, vol. 258, pp. 517-526, 2018/04/01/ 2018.
[27] Y. Hu, O. K. Tan, J. S. Pan, H. Huang, and W. Cao, "The effects of annealing temperature on the sensing properties of low temperature nano-sized SrTiO3 oxygen gas sensor," Sensors and Actuators B: Chemical, vol. 108, no. 1-2, pp. 244-249, 2005.
[28] V. Sugiawati, F. Vacandio, C. Perrin-Pellegrino, A. Galeyeva, A. Kurbatov, and T. Djenizian, "Sputtered porous Li-Fe-PO film cathodes prepared by radio frequency sputtering for Li-ion microbatteries," Scientific Reports, vol. 9, no. 1, p. 11172, 2019.
[29] J. F. Moulder, "The impact of the scanning XPS microprobe on industrial applications of X-ray photoelectron spectroscopy," Journal of Electron Spectroscopy and Related Phenomena, vol. 231, pp. 43-49, 2019/02/01/ 2019.
[30] P. Mohammadi Dashtaki and N. Noormohammadi, "Static analysis of orthotropic nanoplates reinforced by defective graphene based on strain gradient theory using a simple boundary method," Acta Mechanica, vol. 234, no. 11, pp. 5203-5228, 2023.
[31] G. F. Harrington and J. Santiso, "Back-to-Basics tutorial: X-ray diffraction of thin films," Journal of Electroceramics, vol. 47, no. 4, pp. 141-163, 2021.
[32] F.-Y. Zhu, Q.-Q. Wang, X.-S. Zhang, W. Hu, X. Zhao, and H.-X. Zhang, "3D nanostructure reconstruction based on the SEM imaging principle, and applications," Nanotechnology, vol. 25, no. 18, p. 185705, 2014.
[33] M. Veale, Charge transport and low temperature phenomena in single crystal CdZnTe. University of Surrey (United Kingdom), 2009.
[34] H. Cui, K. Zheng, Z. Xie, J. Yu, X. Zhu, H. Ren, Z. Wang, F. Zhang, X. Li, and L.-Q. Tao, "Tellurene nanoflake-based NO2 sensors with superior sensitivity and a sub-parts-per-billion detection limit," ACS Applied Materials & Interfaces, vol. 12, no. 42, pp. 47704-47713, 2020.
[35] J. Jaiswal, P. Singh, and R. Chandra, "Low-temperature highly selective and sensitive NO2 gas sensors using CdTe-functionalized ZnO filled porous Si hybrid hierarchical nanostructured thin films," Sensors and Actuators B: Chemical, vol. 327, p. 128862, 2021.
[36] Y. Su, M. Yao, G. Xie, H. Pan, H. Yuan, M. Yang, H. Tai, X. Du, and Y. Jiang, "Improving sensitivity of self-powered room temperature NO2 sensor by triboelectric-photoelectric coupling effect," Applied Physics Letters, vol. 115, no. 7, 2019.
[37] A. V. Agrawal, N. Kumar, and M. Kumar, "Strategy and future prospects to develop room-temperature-recoverable NO 2 gas sensor based on two-dimensional molybdenum disulfide," Nano-micro letters, vol. 13, pp. 1-58, 2021.
[38] J.-L. Fan, X.-F. Hu, W.-W. Qin, Z.-Y. Liu, Y.-S. Liu, S.-J. Gao, L.-P. Tan, J.-L. Yang, L.-B. Luo, and W. Zhang, "UV-light-assisted gas sensor based on PdSe 2/InSe heterojunction for ppb-level NO 2 sensing at room temperature," Nanoscale, vol. 14, no. 36, pp. 13204-13213, 2022.
[39] Z.-H. Shi, Y.-J. Hsiao, S.-C. Wang, and W.-C. Tien, "InOx doped SnO2 nanostructure deposited on MEMS device by PE-ALD process for detection of NO2," Journal of The Electrochemical Society, vol. 170, no. 2, p. 027509, 2023.
[40] Y. Lu, L. Wang, D. Wang, T. Xie, L. Chen, and Y. Lin, "A comparative study on plate-like and flower-like ZnO nanocrystals surface photovoltage property and photocatalytic activity," Materials Chemistry and Physics, vol. 129, no. 1-2, pp. 281-287, 2011.
[41] M. Zheng, P. Gui, X. Wang, G. Zhang, J. Wan, H. Zhang, G. Fang, H. Wu, Q. Lin, and C. Liu, "ZnO ultraviolet photodetectors with an extremely high detectivity and short response time," Applied Surface Science, vol. 481, pp. 437-442, 2019.
[42] P. Mahajan, R. Datt, V. Gupta, and S. Arya, "Synthesis and characterization of ZnO@ WO3 core/shell nanoparticles as counter electrode for dye-sensitized solar cell," Surfaces and Interfaces, vol. 30, p. 101920, 2022.
[43] Y. Nagaraju, H. Ganesh, S. Veeresha, H. Vijeth, and H. Devendrappa, "Synthesis of hierarchical ZnO/NiO nanocomposite Wurtz hexagonal nanorods via hydrothermal for high-performance symmetric supercapacitor application," Journal of Energy Storage, vol. 56, p. 105924, 2022.
[44] N. Sun, Q. Tian, W. Bian, X. Wang, H. Dou, C. Li, Y. Zhang, C. Gong, X. You, and X. Du, "Highly sensitive and lower detection-limit NO2 gas sensor based on Rh-doped ZnO nanofibers prepared by electrospinning," Applied Surface Science, vol. 614, p. 156213, 2023.
[45] J. Wang, S. Fan, Y. Xia, C. Yang, and S. Komarneni, "Room-temperature gas sensors based on ZnO nanorod/Au hybrids: Visible-light-modulated dual selectivity to NO2 and NH3," Journal of hazardous materials, vol. 381, p. 120919, 2020.
[46] Y. Wang, Y. Cui, X. Meng, Z. Zhang, and J. Cao, "A gas sensor based on Ag-modified ZnO flower-like microspheres: Temperature-modulated dual selectivity to CO and CH4," Surfaces and interfaces, vol. 24, p. 101110, 2021.
[47] M. Hjiri, F. Bahanan, M. Aida, L. El Mir, and G. Neri, "High performance CO gas sensor based on ZnO nanoparticles," Journal of Inorganic and Organometallic Polymers and Materials, vol. 30, pp. 4063-4071, 2020.
[48] Q. Zhang, Z. Pang, W. Hu, J. Li, Y. Liu, Y. Liu, F. Yu, C. Zhang, and M. Xu, "Performance degradation mechanism of the light-activated room temperature NO2 gas sensor based on Ag-ZnO nanoparticles," Applied Surface Science, vol. 541, p. 148418, 2021.
[49] H. Varudkar, G. Umadevi, P. Nagaraju, J. Dargad, and V. Mote, "Fabrication of Al-doped ZnO nanoparticles and their application as a semiconductor-based gas sensor for the detection of ammonia," Journal of Materials Science: Materials in Electronics, vol. 31, no. 15, pp. 12579-12585, 2020.
[50] T.-J. Hsueh, C.-H. Peng, and W.-S. Chen, "A transparent ZnO nanowire MEMS gas sensor prepared by an ITO micro-heater," Sensors and Actuators B: Chemical, vol. 304, p. 127319, 2020.
[51] I. S. Jeon, G. Bae, M. Jang, Y. Yoon, S. Jang, W. Song, S. Myung, J. Lim, S. S. Lee, and H.-K. Jung, "Atomic-level mediation in structural interparameter tradeoff of zinc oxide nanowires-based gas sensors: ZnO nanofilm/ZnO nanowire homojunction array," Applied Surface Science, vol. 540, p. 148350, 2021.
[52] J. Lee, S.-H. Lee, S.-Y. Bak, Y. Kim, K. Woo, S. Lee, Y. Lim, and M. Yi, "Improved sensitivity of α-Fe2O3 nanoparticle-decorated ZnO nanowire gas sensor for CO," Sensors, vol. 19, no. 8, p. 1903, 2019.
[53] X. Wang, X. Wang, X. Sui, W. Zhang, H. Jiang, G. Liu, B. Li, J. Zhou, Y. Sheng, and E. Xie, "ZnO nanowire/NiO foam 3D nanostructures for high-performance ethylene glycol sensing," Sensors and Actuators B: Chemical, vol. 400, p. 134918, 2024.
[54] L. Zhou, J. Bai, Y. Liu, F. Liu, H. Wang, Y. Zhang, and G. Lu, "Highly sensitive C2H2 gas sensor based on Ag modified ZnO nanorods," Ceramics International, vol. 46, no. 10, pp. 15764-15771, 2020.
[55] H. R. Madvar, Z. Kordrostami, and A. Mirzaei, "Sensitivity enhancement of resistive ethanol gas sensor by optimized sputtered-assisted CuO decoration of ZnO nanorods," Sensors, vol. 23, no. 1, p. 365, 2022.
[56] S. Zhao, Y. Shen, X. Yan, P. Zhou, Y. Yin, R. Lu, C. Han, B. Cui, and D. Wei, "Complex-surfactant-assisted hydrothermal synthesis of one-dimensional ZnO nanorods for high-performance ethanol gas sensor," Sensors and Actuators B: Chemical, vol. 286, pp. 501-511, 2019.
[57] A. Thamer, A. Faisal, A. Abed, and W. Khalef, "Synthesis of gold-coated branched ZnO nanorods for gas sensor fabrication," Journal of Nanoparticle Research, vol. 22, no. 4, p. 74, 2020.
[58] A. Sanger, S. B. Kang, M. H. Jeong, C. U. Kim, J. M. Baik, and K. J. Choi, "All-transparent NO2 gas sensors based on freestanding Al-doped ZnO nanofibers," ACS Applied Electronic Materials, vol. 1, no. 7, pp. 1261-1268, 2019.
[59] M. Bonyani, S. M. Zebarjad, K. Janghorban, J.-Y. Kim, H. W. Kim, and S. S. Kim, "Au-decorated polyaniline-ZnO electrospun composite nanofiber gas sensors with enhanced response to NO2 gas," Chemosensors, vol. 10, no. 10, p. 388, 2022.
[60] T. Wei, W. Li, J. Zhang, and X. Xie, "Synthesis of Tb2O3/ZnO composite nanofibers via electrospinning as chemiresistive gas sensor for detecting NO gas," Journal of Alloys and Compounds, vol. 947, p. 169651, 2023.
[61] R. Kumar, S. Singh, and A. Misra, "Development of NO2 gas sensor based on plasma polymerized nanostructure polyaniline thin film," J. Miner. Mater. Charact. Eng, vol. 9, no. 11, pp. 997-1006, 2010.
[62] J.-C. Jian, Y.-C. Chang, S.-P. Chang, and S.-J. Chang, "Biotemplate-Assisted Growth of ZnO in Gas Sensors for ppb-Level NO2 Detection," ACS omega, vol. 9, no. 1, pp. 1077-1083, 2023.
[63] M. Farooq, S. Sagbas, M. Sahiner, M. Siddiq, M. Turk, N. Aktas, and N. Sahiner, "Synthesis, characterization and modification of Gum Arabic microgels for hemocompatibility and antimicrobial studies," Carbohydrate polymers, vol. 156, pp. 380-389, 2017.
[64] R. M. Daoub, A. H. Elmubarak, M. Misran, E. A. Hassan, and M. E. Osman, "Characterization and functional properties of some natural Acacia gums," Journal of the Saudi Society of Agricultural Sciences, vol. 17, no. 3, pp. 241-249, 2018.
[65] H. H. Musa, A. A. Ahmed, and T. H. Musa, "Chemistry, biological, and pharmacological properties of gum Arabic," Bioactive molecules in food, pp. 1-18, 2018.
[66] J. P. Goncalves, C. C. de Oliveira, E. da Silva Trindade, I. C. Riegel-Vidotti, M. Vidotti, and F. F. Simas, "In vitro biocompatibility screening of a colloidal gum Arabic-polyaniline conducting nanocomposite," International Journal of Biological Macromolecules, vol. 173, pp. 109-117, 2021.
[67] S. Abinaya, H. P. Kavitha, M. Prakash, and A. Muthukrishnaraj, "Green synthesis of magnesium oxide nanoparticles and its applications: A review," Sustainable Chemistry and Pharmacy, vol. 19, p. 100368, 2021.
[68] Y.-T. Tsai, S.-J. Chang, L.-W. Ji, Y.-J. Hsiao, I.-T. Tang, H.-Y. Lu, and Y.-L. Chu, "High sensitivity of NO gas sensors based on novel Ag-doped ZnO nanoflowers enhanced with a UV light-emitting diode," ACS omega, vol. 3, no. 10, pp. 13798-13807, 2018.
[69] C.-L. Kuo, T.-J. Kuo, and M. H. Huang, "Hydrothermal synthesis of ZnO microspheres and hexagonal microrods with sheetlike and platelike nanostructures," The Journal of Physical Chemistry B, vol. 109, no. 43, pp. 20115-20121, 2005.
[70] N. S. El-Sayed, A. H. Hashem, and S. Kamel, "Preparation and characterization of Gum Arabic Schiff's bases based on 9-aminoacridine with in vitro evaluation of their antimicrobial and antitumor potentiality," Carbohydrate Polymers, vol. 277, p. 118823, 2022.
[71] M. M. Ba-Abbad, M. S. Takriff, A. Benamor, E. Mahmoudi, and A. W. Mohammad, "Arabic gum as green agent for ZnO nanoparticles synthesis: properties, mechanism and antibacterial activity," Journal of Materials Science: Materials in Electronics, vol. 28, pp. 12100-12107, 2017.
[72] S. Amirabadi, J. M. Milani, and F. Sohbatzadeh, "Application of dielectric barrier discharge plasma to hydrophobically modification of gum arabic with enhanced surface properties," Food Hydrocolloids, vol. 104, p. 105724, 2020.
[73] N. Pauzi, N. M. Zain, and N. A. A. Yusof, "Gum arabic as natural stabilizing agent in green synthesis of ZnO nanofluids for antibacterial application," Journal of Environmental Chemical Engineering, vol. 8, no. 3, p. 103331, 2020.
[74] M. Chelu, J. C. Moreno, I. Atkinson, J. P. Cusu, A. Rusu, V. Bratan, L. Aricov, M. Anastasescu, A.-M. Seciu-Grama, and A. M. Musuc, "Green synthesis of bioinspired chitosan-ZnO-based polysaccharide gums hydrogels with propolis extract as novel functional natural biomaterials," International Journal of Biological Macromolecules, vol. 211, pp. 410-424, 2022.
[75] A. C. Pandey, S. S. Sanjay, and R. S. Yadav, "Application of ZnO nanoparticles in influencing the growth rate of Cicer arietinum," Journal of Experimental nanoscience, vol. 5, no. 6, pp. 488-497, 2010.
[76] A. De, D. Malpani, B. Das, D. Mitra, and A. Samanta, "Characterization of an arabinogalactan isolated from gum exudate of Odina wodier Roxb.: Rheology, AFM, Raman and CD spectroscopy," Carbohydrate polymers, vol. 250, p. 116950, 2020.
[77] Z.-N. Ng, K.-Y. Chan, and T. Tohsophon, "Effects of annealing temperature on ZnO and AZO films prepared by sol–gel technique," Applied Surface Science, vol. 258, no. 24, pp. 9604-9609, 2012.
[78] S. Deng, R. Han, C. Dong, X. Xiao, J. Wu, and Y. Wang, "Flash synthesis of macro-/nanoporous ZnCo2O4 via self-sustained decomposition of metal–organic complexes," Materials Letters, vol. 134, pp. 138-141, 2014.
[79] Z. Ye, T. Wang, S. Wu, X. Ji, and Q. Zhang, "Na-doped ZnO nanorods fabricated by chemical vapor deposition and their optoelectrical properties," Journal of Alloys and Compounds, vol. 690, pp. 189-194, 2017.
[80] J. Zheng, Q. Jiang, and J. Lian, "Synthesis and optical properties of flower-like ZnO nanorods by thermal evaporation method," Applied Surface Science, vol. 257, no. 11, pp. 5083-5087, 2011.
[81] M. R. Alenezi, A. S. Alshammari, K. I. Jayawardena, M. J. Beliatis, S. J. Henley, and S. Silva, "Role of the exposed polar facets in the performance of thermally and UV activated ZnO nanostructured gas sensors," The Journal of Physical Chemistry C, vol. 117, no. 34, pp. 17850-17858, 2013.
[82] P.-T. Hsieh, Y.-C. Chen, K.-S. Kao, and C.-M. Wang, "Luminescence mechanism of ZnO thin film investigated by XPS measurement," Applied Physics A, vol. 90, pp. 317-321, 2008.
[83] N. Han, X. Wu, L. Chai, H. Liu, and Y. Chen, "Counterintuitive sensing mechanism of ZnO nanoparticle based gas sensors," sensors and actuators B: chemical, vol. 150, no. 1, pp. 230-238, 2010.
[84] C. Li, Y.-Y. Sun, Y.-N. Li, X.-F. Zhang, Z.-P. Deng, L.-H. Huo, Y.-M. Xu, and S. Gao, "Low-temperature and high-response NO2 sensor based on oxygen vacancy-enriched ZnO tubes inherited from waste chestnut mesocarps," Sensors and Actuators B: Chemical, vol. 388, p. 133838, 2023.
[85] H.-B. Na, X.-F. Zhang, M. Zhang, Z.-P. Deng, X.-L. Cheng, L.-H. Huo, and S. Gao, "A fast response/recovery ppb-level H2S gas sensor based on porous CuO/ZnO heterostructural tubule via confined effect of absorbent cotton," Sensors and Actuators B: Chemical, vol. 297, p. 126816, 2019.
[86] E. Thauer, G. Zakharova, E. Andreikov, V. Adam, S. Wegener, J.-H. Nölke, L. Singer, A. Ottmann, A. Asyuda, and M. Zharnikov, "Novel synthesis and electrochemical investigations of ZnO/C composites for lithium-ion batteries," Journal of Materials Science, vol. 56, no. 23, pp. 13227-13242, 2021.
[87] G. Qu, G. Fan, M. Zhou, X. Rong, T. Li, R. Zhang, J. Sun, and D. Chen, "Graphene-modified ZnO nanostructures for low-temperature NO2 sensing," ACS omega, vol. 4, no. 2, pp. 4221-4232, 2019.
[88] M. Chougule, S. Sen, and V. Patil, "Fabrication of nanostructured ZnO thin film sensor for NO2 monitoring," Ceramics International, vol. 38, no. 4, pp. 2685-2692, 2012.
[89] V. Shinde, T. Gujar, and C. Lokhande, "LPG sensing properties of ZnO films prepared by spray pyrolysis method: effect of molarity of precursor solution," Sensors and actuators B: Chemical, vol. 120, no. 2, pp. 551-559, 2007.
[90] S. M. Hafiz, R. Ritikos, T. J. Whitcher, N. M. Razib, D. C. S. Bien, N. Chanlek, H. Nakajima, T. Saisopa, P. Songsiriritthigul, and N. M. Huang, "A practical carbon dioxide gas sensor using room-temperature hydrogen plasma reduced graphene oxide," Sensors and Actuators B: Chemical, vol. 193, pp. 692-700, 2014.
[91] X. Deng, L. Zhang, J. Guo, Q. Chen, and J. Ma, "ZnO enhanced NiO-based gas sensors towards ethanol," Materials Research Bulletin, vol. 90, pp. 170-174, 2017.
[92] H. Wang, J. Bai, M. Dai, K. Liu, Y. Liu, L. Zhou, F. Liu, F. Liu, Y. Gao, and X. Yan, "Visible light activated excellent NO2 sensing based on 2D/2D ZnO/g-C3N4 heterojunction composites," Sensors and Actuators B: Chemical, vol. 304, p. 127287, 2020.
[93] S. Saini, A. Kumar, S. Ranwa, and A. Tyagi, "Highly sensitive NO2 gas sensor based on Ag decorated ZnO nanorods," Applied Physics A, vol. 128, no. 5, p. 454, 2022.
[94] V. Patil, D. Dalavi, S. Dhavale, N. Tarwal, S. Vanalakar, A. Kalekar, J. Kim, and P. Patil, "NO2 gas sensing properties of chemically grown Al doped ZnO nanorods," Sensors and Actuators A: Physical, vol. 340, p. 113546, 2022.
[95] Y. Nagarjuna and Y.-J. Hsiao, "TeO2 doped ZnO nanostructure for the enhanced NO2 gas sensing on MEMS sensor device," Sensors and Actuators B: Chemical, vol. 401, p. 134891, 2024.
[96] V. Ganbavle, S. Inamdar, G. Agawane, J. Kim, and K. Rajpure, "Synthesis of fast response, highly sensitive and selective Ni: ZnO based NO2 sensor," Chemical Engineering Journal, vol. 286, pp. 36-47, 2016.
[97] R. Ambi, A. Mane, V. Patil, and R. Mane, "Highly porous hierarchical NiO coated ZnO pn heterostructure for NO2 detection," Materials Science and Engineering: B, vol. 300, p. 117066, 2024.
[98] R. R. Kumar, W.-C. Yu, T. Murugesan, P.-C. Chen, A. Ranjan, M.-Y. Lu, and H.-N. Lin, "Formation of large-scale MoS2/Cu2O/ZnO heterostructure arrays by in situ photodeposition and application for ppb-level NO2 gas sensing," Journal of Alloys and Compounds, vol. 952, p. 169984, 2023.
[99] S.-F. Tseng, P.-S. Chen, S.-H. Hsu, W.-T. Hsiao, and W.-J. Peng, "Investigation of fiber laser-induced porous graphene electrodes in controlled atmospheres for ZnO nanorod-based NO2 gas sensors," Applied Surface Science, vol. 620, p. 156847, 2023.
[100] P. H. Phuoc, N. N. Viet, C. M. Hung, N. D. Hoa, N. Van Duy, H. S. Hong, and N. Van Hieu, "Comparative study on the gas-sensing performance of ZnO/SnO2 external and ZnO–SnO2 internal heterojunctions for ppb H2S and NO2 gases detection," Sensors and Actuators B: Chemical, vol. 334, p. 129606, 2021.
[101] P. Cao, Y. Cai, D. Pawar, S. Navale, C. N. Rao, S. Han, W. Xu, M. Fang, X. Liu, and Y. Zeng, "Down to ppb level NO2 detection by ZnO/rGO heterojunction based chemiresistive sensors," Chemical Engineering Journal, vol. 401, p. 125491, 2020.
[102] A. Mirzaei, J.-H. Lee, S. M. Majhi, M. Weber, M. Bechelany, H. W. Kim, and S. S. Kim, "Resistive gas sensors based on metal-oxide nanowires," Journal of Applied Physics, vol. 126, no. 24, 2019.
[103] W.-D. Li and S. Y. Chou, "Solar-blind deep-UV band-pass filter (250 - 350 nm) consisting of a metal nano-grid fabricated by nanoimprint lithography," Opt. Express, vol. 18, no. 2, pp. 931-937, 2010/01/18 2010.
[104] M. Razeghi and A. Rogalski, "Semiconductor ultraviolet detectors," Journal of Applied Physics, vol. 79, no. 10, pp. 7433-7473, 1996.
[105] P. Li, H. Shi, K. Chen, D. Guo, W. Cui, Y. Zhi, S. Wang, Z. Wu, Z. Chen, and W. Tang, "Construction of GaN/Ga2O3 p–n junction for an extremely high responsivity self-powered UV photodetector," Journal of Materials Chemistry C, 10.1039/C7TC03746E vol. 5, no. 40, pp. 10562-10570, 2017.
[106] Z. Wu, L. Jiao, X. Wang, D. Guo, W. Li, L. Li, F. Huang, and W. Tang, "A self-powered deep-ultraviolet photodetector based on an epitaxial Ga2O3/Ga:ZnO heterojunction," Journal of Materials Chemistry C, 10.1039/C7TC01741C vol. 5, no. 34, pp. 8688-8693, 2017.
[107] Y. Luo, Z. Dong, Y. Chen, Y. Zhang, Y. Lu, T. Xia, L. Wang, S. Li, W. Zhang, W. Xiang, C. Shan, and H. Guo, "Self-powered NiO@ZnO-nanowire-heterojunction ultraviolet micro-photodetectors," Opt. Mater. Express, vol. 9, no. 7, pp. 2775-2784, 2019/07/01 2019.
[108] C. Zhou, Q. Ai, X. Chen, X. Gao, K. Liu, and D. Shen, "Ultraviolet photodetectors based on wide bandgap oxide semiconductor films*," Chinese Physics B, vol. 28, no. 4, p. 048503, 2019/04/01 2019.
[109] R. Ghosh, M. Dutta, and D. Basak, "Self-seeded growth and ultraviolet photoresponse properties of ZnO nanowire arrays," Applied Physics Letters, vol. 91, no. 7, p. 073108, 2007.
[110] Y. He, W. Zhang, S. Zhang, X. Kang, W. Peng, and Y. Xu, "Study of the photoconductive ZnO UV detector based on the electrically floated nanowire array," Sensors and Actuators A: Physical, vol. 181, pp. 6-12, 2012/07/01/ 2012.
[111] R. Rasmidi, M. Duinong, and F. P. Chee, "Radiation damage effects on zinc oxide (ZnO) based semiconductor devices– a review," Radiation Physics and Chemistry, vol. 184, p. 109455, 2021/07/01/ 2021.
[112] E. W. Seelig, B. Tang, A. Yamilov, H. Cao, and R. P. H. Chang, "Self-assembled 3D photonic crystals from ZnO colloidal spheres," Materials Chemistry and Physics, vol. 80, no. 1, pp. 257-263, 2003/04/29/ 2003.
[113] L. Zhu and W. Zeng, "Room-temperature gas sensing of ZnO-based gas sensor: A review," Sensors and Actuators A: Physical, vol. 267, pp. 242-261, 2017/11/01/ 2017.
[114] T. Bi, Z. Du, S. Chen, H. He, X. Shen, and Y. Fu, "Preparation of flower-like ZnO photocatalyst with oxygen vacancy to enhance the photocatalytic degradation of methyl orange," Applied Surface Science, vol. 614, p. 156240, 2023/03/30/ 2023.
[115] H. Son, Y.-W. Heo, and B.-S. Jeong, "Efficiency optimization of All-Inorganic perovskite solar cell device using NiOx and ZnO as charge transport layers," Solar Energy, vol. 281, p. 112892, 2024/10/01/ 2024.
[116] P. Salunkhe, P. Bhat, and D. Kekuda, "Performance evaluation of transparent self-powered n-ZnO/p-NiO heterojunction ultraviolet photosensors," Sensors and Actuators A: Physical, vol. 345, p. 113799, 2022/10/01/ 2022.
[117] L. Chen, L. Chen, J. Chu, S. Yang, Z. Ma, Z. Jia, and J. Song, "From UV to Vis Broadband Photodetectors Based on ZnO/CuO/NiO Core–Shell–Shell Heterojunction Nanostructures," ACS Applied Nano Materials, vol. 6, no. 11, pp. 9968-9974, 2023/06/09 2023.
[118] D. Kawade, S. F. Chichibu, and M. Sugiyama, "Experimental determination of band offsets of NiO-based thin film heterojunctions," Journal of Applied Physics, vol. 116, no. 16, p. 163108, 2014.
[119] D. Kawade, S. F. Chichibu, and M. Sugiyama, "Experimental determination of band offsets of NiO-based thin film heterojunctions," Journal of applied physics, vol. 116, no. 16, 2014.
[120] X. Zheng, Y. Sun, H. Qin, and Z. Ji, "Solar-charged pseudocapacitors: simultaneous conversion and storage of solar energy in ZnO@ NiO nanorod arrays," Journal of Alloys and Compounds, vol. 781, pp. 351-356, 2019.
[121] P. Sahoo, A. Sharma, S. Padhan, and R. Thangavel, "Construction of ZnO@NiO heterostructure photoelectrodes for improved photoelectrochemical performance," International Journal of Hydrogen Energy, vol. 46, no. 73, pp. 36176-36188, 2021/10/22/ 2021.
[122] A. A. Mariod, "Functional properties of gum Arabic," in Gum Arabic: Elsevier, 2018, pp. 283-295.
[123] M. A. H. Shiam, M. S. Islam, I. Ahmad, and S. S. Haque, "A review of plant-derived gums and mucilages: Structural chemistry, film forming properties and application," Journal of Plastic Film & Sheeting, p. 87560879251316553, 2025.
[124] M. B. Elamin, A. Chrouda, S. M. A. Ali, L. M. Alhaidari, M. Jabli, R. M. Alrouqi, and N. J. Renault, "Electrochemical sensor based on gum Arabic nanoparticles for rapid and in-situ detection of different heavy metals in real samples," Heliyon, vol. 10, no. 4, 2024.
[125] G. Yang and S.-J. Park, "Conventional and microwave hydrothermal synthesis and application of functional materials: A review," Materials, vol. 12, no. 7, p. 1177, 2019.
[126] M. A. Butt, "Thin-film coating methods: a successful marriage of high-quality and cost-effectiveness—a brief exploration," Coatings, vol. 12, no. 8, p. 1115, 2022.
[127] A. Echresh, M. A. Abbasi, M. Z. Shoushtari, M. Farbod, O. Nur, and M. Willander, "Optimization and characterization of NiO thin film and the influence of thickness on the electrical properties of n-ZnO nanorods/p-NiO heterojunction," Semiconductor Science and Technology, vol. 29, no. 11, p. 115009, 2014.
[128] C. Kim, H. Min, J. Kim, J. Sul, J. Yang, and J. H. Moon, "NiO/ZnO heterojunction nanorod catalyst for high-efficiency electrochemical conversion of methane," Applied Catalysis B: Environmental, vol. 323, p. 122129, 2023.
[129] P. Li, Y. Liu, J. Liu, Z. Li, G. Wu, and M. Wu, "Facile synthesis of ZnO/mesoporous carbon nanocomposites as high-performance anode for lithium-ion battery," Chemical Engineering Journal, vol. 271, pp. 173-179, 2015.
[130] V. Sudha, S. M. S. Kumar, and R. Thangamuthu, "Synthesis and characterization of NiO nanoplatelet and its application in electrochemical sensing of sulphite," Journal of Alloys and Compounds, vol. 744, pp. 621-628, 2018.
[131] R. Al-Gaashani, S. Radiman, A. Daud, N. Tabet, and Y. Al-Douri, "XPS and optical studies of different morphologies of ZnO nanostructures prepared by microwave methods," Ceramics International, vol. 39, no. 3, pp. 2283-2292, 2013.
[132] B. Zhang, X. Shang, Z. Jiang, C. Song, T. Maiyalagan, and Z.-J. Jiang, "Atmospheric-pressure plasma jet-induced ultrafast construction of an ultrathin nonstoichiometric nickel oxide layer with mixed Ni3+/Ni2+ ions and rich oxygen defects as an efficient electrocatalyst for oxygen evolution reaction," ACS Applied Energy Materials, vol. 4, no. 5, pp. 5059-5069, 2021.
[133] A. Echresh, C. O. Chey, M. Z. Shoushtari, V. Khranovskyy, O. Nur, and M. Willander, "UV photo-detector based on p-NiO thin film/n-ZnO nanorods heterojunction prepared by a simple process," Journal of alloys and compounds, vol. 632, pp. 165-171, 2015.
[134] J. Zhang and J. Li, "The oxygen vacancy defect of ZnO/NiO nanomaterials improves photocatalytic performance and ammonia sensing performance," Nanomaterials, vol. 12, no. 3, p. 433, 2022.
[135] M. Patel, H.-S. Kim, J. Kim, J.-H. Yun, S. J. Kim, E. H. Choi, and H.-H. Park, "Excitonic metal oxide heterojunction (NiO/ZnO) solar cells for all-transparent module integration," Solar energy materials and solar cells, vol. 170, pp. 246-253, 2017.
[136] S. Yin, C. H. Y. Ho, S. Ding, X. Fu, L. Zhu, J. Gullett, C. Dong, and F. So, "Enhanced surface passivation of lead sulfide quantum dots for short-wavelength photodetectors," Chemistry of Materials, vol. 34, no. 12, pp. 5433-5442, 2022.
[137] Y. Xu, H. Li, B. Sun, P. Qiao, L. Ren, G. Tian, B. Jiang, K. Pan, and W. Zhou, "Surface oxygen vacancy defect-promoted electron-hole separation for porous defective ZnO hexagonal plates and enhanced solar-driven photocatalytic performance," Chemical Engineering Journal, vol. 379, p. 122295, 2020.
[138] L. Che, J. Pan, K. Cai, Y. Cong, and S.-W. Lv, "The construction of pn heterojunction for enhancing photocatalytic performance in environmental application: A review," Separation and Purification Technology, vol. 315, p. 123708, 2023.
[139] C.-Y. Tsay, Y.-C. Chen, H.-M. Tsai, and F.-H. Lu, "Photoresponse of solution-processed transparent heterojunction ultraviolet photodetectors composed of n-type ZTO and p-type NiO-based semiconductor thin films," Materials Chemistry and Physics, vol. 295, p. 127143, 2023.
[140] L. Su, Q. Zhang, T. Wu, M. Chen, Y. Su, Y. Zhu, R. Xiang, X. Gui, and Z. Tang, "High-performance zero-bias ultraviolet photodetector based on p-GaN/n-ZnO heterojunction," Applied Physics Letters, vol. 105, no. 7, 2014.
[141] Y. Zhang, W. Xu, X. Xu, W. Yang, S. Li, J. Chen, and X. Fang, "Low-cost writing method for self-powered paper-based UV photodetectors utilizing Te/TiO 2 and Te/ZnO heterojunctions," Nanoscale Horizons, vol. 4, no. 2, pp. 452-456, 2019.
[142] T. Park and J. Hur, "Self‐powered low‐cost UVC sensor based on organic‐inorganic heterojunction for partial discharge detection," Small, vol. 17, no. 28, p. 2100695, 2021.
[143] C. W. Na, H.-S. Woo, and J.-H. Lee, "Design of highly sensitive volatile organic compound sensors by controlling NiO loading on ZnO nanowire networks," RSC advances, vol. 2, no. 2, pp. 414-417, 2011.
[144] Z. Zhang, Y. Ning, and X. Fang, "From nanofibers to ordered ZnO/NiO heterojunction arrays for self-powered and transparent UV photodetectors," Journal of Materials Chemistry C, vol. 7, no. 2, pp. 223-229, 2019.
[145] N. Park, K. Sun, Z. Sun, Y. Jing, and D. Wang, "High efficiency NiO/ZnO heterojunction UV photodiode by sol–gel processing," Journal of Materials Chemistry C, vol. 1, no. 44, pp. 7333-7338, 2013.
[146] B. Yin, Y. Qiu, H. Zhang, Y. Chang, D. Yang, and L. Hu, "Enhancing performance of ZnO/NiO UV photodetector by piezo-phototronic effect," Rsc Advances, vol. 6, no. 54, pp. 48319-48323, 2016.
[147] J.-D. Hwang and C.-Y. Liao, "Enhancement of UV response and suppression of visible response of p-Si/n-ZnO heterojunction photodiodes via NiO and MgO insertion layers," The Journal of Physical Chemistry C, vol. 124, no. 23, pp. 12734-12741, 2020.
[148] M. Hilal, Y. Ali, Z. Cai, H. Kim, H. S. Abdo, I. A. Alnaser, and Y. Hwang, "Synergistic MXene@ NiO-ZnO Heterostructures via Dual-Pressure Hydrothermal Synthesis for High-Performance Photoelectrochemical Glucose Sensing," Ceramics International, 2025.
[149] Y. Shen, X. Yan, Z. Bai, X. Zheng, Y. Sun, Y. Liu, P. Lin, X. Chen, and Y. Zhang, "A self-powered ultraviolet photodetector based on solution-processed p-NiO/n-ZnO nanorod array heterojunction," Rsc Advances, vol. 5, no. 8, pp. 5976-5981, 2014.
[150] J. Zou, Q. Zhang, K. Huang, and N. Marzari, "Ultraviolet photodetectors based on anodic TiO2 nanotube arrays," The Journal of Physical Chemistry C, vol. 114, no. 24, pp. 10725-10729, 2010.
[151] W. Tian, C. Zhang, T. Zhai, S. L. Li, X. Wang, J. Liu, X. Jie, D. Liu, M. Liao, and Y. Koide, "Flexible ultraviolet photodetectors with broad photoresponse based on branched ZnS‐ZnO heterostructure nanofilms," Advanced Materials, vol. 26, no. 19, pp. 3088-3093, 2014.