Fabrication and Characterisation of TiO2 Thin Film Methanol Vapor Sensor

Öz

In this study, titanium dioxide (TiO₂) thin film with a thickness of approximately 250 nm was deposited on silicon dioxide (SiO₂) substrate using the pulsed DC sputtering technique to investigate gas sensing performance of methanol vapor detection. The structural, morphological, and vibrational characteristics of the film was analysed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and micro-Raman spectroscopy, respectively. UV–Vis spectrophotometry was used to analyse the optical properties, including light absorption behaviour, and to determine the band gap of the sensing material. For sensor measurements under methanol vapor ambient, aluminium interdigitated electrodes (IDEs) ohmic contacts were fabricated on the surface of the TiO₂ film using DC sputtering. The sensor was subsequently exposed to various concentrations of methanol vapor (up to 1900 ppm) at three different operating temperatures: 150 °C, 200 °C, and 250 °C. The dynamic gas sensing performance, including response and recovery times, was systematically monitored under each condition. The highest response was recorded at 250 °C, where the sensor exhibited a Ra/Rg value of 6.3 upon exposure to 1900 ppm methanol, along with the shortest response and recovery times. In contrast, at lower operating temperatures (150 °C and 200 °C), the sensor response decreased, and both the response and recovery times were significantly prolonged

Anahtar Kelimeler

• TiO2 Thin Film
• Sensor
• Chemical Vapor
• Methanol

TiO₂ İnce Film Metanol Buharı Sensörünün Üretimi ve Karakterizasyonu

Öz

Bu çalışmada, yaklaşık 250 nm kalınlığındaki titanyum dioksit (TiO₂) ince film, metanol buharının algılanmasına yönelik gaz algılama performansını araştırmak amacıyla pulse DC saçtırma tekniği kullanılarak silisyum dioksit (SiO₂) alttaş üzerine kaplanmıştır. Filmin yapısal, morfolojik ve titreşimsel özellikleri sırasıyla X-ışını kırınımı (XRD), taramalı elektron mikroskobu (SEM) ve mikro-Raman spektroskopisi kullanılarak analiz edilmiştir. Optik özellikler, ışık soğurma davranışı dahil olmak üzere, UV–Vis spektrofotometresi ile incelenmiş ve algılayıcı malzemenin bant aralığı belirlenmiştir. Metanol buharı ortamında sensör ölçümleri gerçekleştirebilmek için, TiO₂ film yüzeyine DC saçtırma yöntemiyle ohmik temas sağlayan alüminyum iç içe geçmiş elektrotlar (IDE) üretilmiştir. Sensör daha sonra üç farklı çalışma sıcaklığında (150 °C, 200 °C ve 250 °C) 1900 ppm’e kadar çeşitli metanol buharı konsantrasyonlarına maruz bırakılmıştır. Her bir koşul altında, yanıt ve iyileşme süreleri dahil olmak üzere dinamik gaz algılama performansı sistematik olarak izlenmiştir. En yüksek tepki, sensörün 250 °C’de 1900 ppm metanol buharına maruz kalmasıyla 6.3 (Ra/Rg)’lük tepki miktarı ve en kısa yanıt ile iyileşme sürelerini gösterdiği durumunda elde edilmiştir. Buna karşılık, daha düşük çalışma sıcaklıklarında (150 °C ve 200 °C) sensör tepkisi azalmış, yanıt ve iyileşme süreleri ise belirgin şekilde uzamıştır.

Anahtar Kelimeler

• TiO2 İnce Film
• Sensör
• Kimyasal Buhar
• Metanol

Kaynakça

1. Hendricks AJ, Thompson AM, Shi VY. 9- Oxidative Stress, Environmental Factors, and Pollutants. In: Chan LS, Shi VY, editors. Atopic Dermatitis: Inside Out Or Outside in. Elsevier; 2023. p. 79–84.
2. Pandey P, Yadav R. A Review on Volatile Organic Compounds (VOCs) as Environmental Pollutants: Fate and Distribution. International Journal Of Plant And Environment. 2018; 4:14–26.
3. Nekoukar Z, Zakariaei Z, Taghizadeh F, Musavi F, Banimostafavi ES, Sharifpour A, et al. Methanol poisoning as a new world challenge: A review. Ann Med Surg (Lond). 2021; 66:102445.
4. Alrashed M, Aldeghaither NS, Almutairi SY, Almutairi M, Alghamdi A, Alqahtani T, et al. The Perils of Methanol Exposure: Insights into Toxicity and Clinical Management. Toxics. 2024; 12:924.
5. Wallace LA. Human exposure to volatile organic pollutants: Implications for Indoor Air Studies. Annual Review of Environment and Resources. 2001; 26:269–301.
6. Organization WH, Safety IP on C, Programme UNE, Organization IL. Methanol: health and safety guide. World Health Organization; 1997.
7. Occupational Safety and Health Administration (OSHA). Methanol [Internet]. [Cited 2025 July 29]. Available from: https://www.osha.gov/chemicaldata/474
8. Dorman FL, Overton EB, Whiting JJ, Cochran JW, Gardea-Torresdey J. Gas Chromatography. Anal Chem. 2008; 80:4487–97.

9. Pontes H, Guedes de Pinho P, Casal S, Carmo H, Santos A, Magalhães T, et al. GC Determination of Acetone, Acetaldehyde, Ethanol, and Methanol in Biological Matrices and Cell Culture. Journal of Chromatographic Science. 2009; 47:272–8.
10. Liu X, Cheng S, Liu H, Hu S, Zhang D, Ning H. A Survey on Gas Sensing Technology. Sensors. 2012; 12:9635–65.
11. Korotcenkov G. Metal oxides for solid-state gas sensors: What determines our choice? Materials Science and Engineering: B. 2007; 139:1–23.
12. Dey A. Semiconductor metal oxide gas sensors: A review. Materials Science and Engineering: B. 2018; 229:206–17.
13. Penza M, Rossi R, Alvisi M, Serra E. Metal-modified and vertically aligned carbon nanotube sensors array for landfill gas monitoring applications. Nanotechnology. 2010; 21:105501.
14. Göpel W, Schierbaum KD. SnO2 sensors: current status and future prospects. Sensors and Actuators B: Chemical. 1995; 26:1–12.
15. Amiri V, Roshan H, Mirzaei A, Neri G, Ayesh AI. Nanostructured Metal Oxide-Based Acetone Gas Sensors: A Review. Sensors. 2020; 20:3096.
16. Mohd Chachuli SA, Hamidon MN, Ertugurl M, Mamat MdS, Coban O, Shamsudin NH, et al. Effects of silver diffusement on TiO2-B2O3 nanocomposite sensor towards hydrogen sensing. Materials Research Innovations. 2024; 28:365–78.
17. Chachuli SAM, Hamidon MN, Ertugrul M, Mamat MS, Coban O, Tuzluca FN, et al. Effects of MWCNTs/graphene nanoflakes/MXene addition to TiO2 thick film on hydrogen gas sensing. Journal of Alloys and Compounds. 2021; 882:160671.
18. Mohd Chachuli SA, Hamidon MN, Ertugrul M, Mamat MdS, Coban O, Shamsudin NH. Comparative analysis of hydrogen sensing based on treated-TiO2 in thick film gas sensor. Appl Phys A. 2022; 128:596.
19. Comini E, Faglia G, Sberveglieri G. UV light activation of tin oxide thin films for NO2 sensing at low temperatures. Sensors and Actuators B: Chemical. 2001; 78:73–7.
20. Zhang J, Liu X, Neri G, Pinna N. Nanostructured Materials for Room-Temperature Gas Sensors. Advanced Materials. 2016; 28:795–831.
21. Diebold U. The surface science of titanium dioxide. Surface Science Reports. 2003; 48:53–229.
22. Tang H, Prasad K, Sanjinès R, Schmid PE, Lévy F. Electrical and optical properties of TiO2 anatase thin films. Journal of Applied Physics. 1994; 75:2042–7.
23. Grätzel M. Photoelectrochemical cells. Nature. 2001; 414:338–44.
24. Yi Q, Hao X, Li X, Dong H, Sun L. Effect of TiO2 nanoparticles on the mass transfer process of absorption of toluene: Experimental investigation and molecular dynamics simulation. Journal of Environmental Chemical Engineering. 2023; 11:109474.
25. Ozden M, Coban O, Karacali T. Fabrication and Characterization of a PZT-Based Touch Sensor Using Combined Spin-Coating and Sputtering Methods. Sensors. 2025; 25:3938.
26. Zhang J-Y, Boyd IW, O’Sullivan BJ, Hurley PK, Kelly PV, Sénateur J-P. Nanocrystalline TiO2 films studied by optical, XRD and FTIR spectroscopy. Journal of Non-Crystalline Solids. 2002; 303:134–8.
27. Srinivasu P, Singh SP, Islam A, Han L. Novel Approach for the Synthesis of Nanocrystalline Anatase Titania and Their Photovoltaic Application. Advances in OptoElectronics. 2011; 2011:539382.
28. Chu L, Qin Z, Yang J, Li X. Anatase TiO2 Nanoparticles with Exposed {001} Facets for Efficient Dye-Sensitized Solar Cells. Sci Rep. 2015; 5:12143.
29. Kuriechen SK, Murugesan S, Paul Raj S. Mineralization of Azo Dye Using Combined Photo-Fenton and Photocatalytic Processes under Visible Light. Journal of Catalysts. 2013; 2013:104019.
30. Challagulla S, Tarafder K, Ganesan R, Roy S. Structure sensitive photocatalytic reduction of nitroarenes over TiO2. Sci Rep. 2017; 7:8783.
31. Vetrivel V, Rajendran DK, Kalaiselvi V. Synthesis and characterization of Pure Titanium dioxide nanoparticles by Sol- gel method.
32. Ekoi EJ, Gowen A, Dorrepaal R, Dowling DP. Characterisation of titanium oxide layers using Raman spectroscopy and optical profilometry: Influence of oxide properties. Results in Physics. 2019; 12:1574–85.
33. Balachandran U, Eror NG. Raman spectra of titanium dioxide. Journal of Solid State Chemistry. 1982; 42:276–82.
34. Ivanda M, Musić S, Popović S, Gotić M. XRD, Raman and FT-IR spectroscopic observations of nanosized TiO2 synthesized by the sol–gel method based on an esterification reaction. Journal of Molecular Structure. 1999;480–481:645–9.
35. Shooshtari M, Salehi A, Vollebregt S. Effect of temperature and humidity on the sensing performance of TiO2 nanowire-based ethanol vapor sensors. Nanotechnology. 2021; 32:325501.
36. Shimizu Y, Egashira M. Basic Aspects and Challenges of Semiconductor Gas Sensors. MRS Bulletin. 1999; 24:18–24.
37. Yamazoe N. New approaches for improving semiconductor gas sensors. Sensors and Actuators B: Chemical. 1991; 5:7–19.
38. Korotcenkov G. The role of morphology and crystallographic structure of metal oxides in response of conductometric-type gas sensors. Materials Science and Engineering: R: Reports. 2008; 61:1–39.