[1] C E Kim, I Yun. Effects of the interfacial layer on electrical properties of TiO₂-based high-k dielectric composite films. ECS Trans, 45, 89(2012).

[2] A Taherniya, D Raoufi. The annealing temperature dependence of anatase TiO₂ thin films prepared by the electron-beam evaporation method. Semicond Sci Technol, 31, 125012(2016).

[3] R S Khaleel, M S Hashim. Fabrication of TiO₂ sensor using rapid breakdown anodization method to measure pressure, humidity and sense gases at room temperature. Iraqi J Sci, 60, 1694(2019).

[4] M Vanmathi, M S Kumar, M M Ismail. Optimization of process parameters for al-doping back ground on CO gas sensing characteristics of magnetron-sputtered TiO₂ sensors. Mater Res Express, 6, 106423(2019).

[5] C H Ashok, K V Rao, C H S Chakra. Comparison of metal oxide nanomaterials: Humidity sensor applications. Mater Energy Environ Eng, 267(2017).

[6] M M Khan, S F Adil, A Al-Mayouf. Metal oxides as photocatalysts. J Saudi Chem Soc, 19, 462(2015).

[7] K Kaviyarasu, N Geetha, K Kanimozhi. In vitro cytotoxicity effect and antibacterial performance of human lung epithelial cells A549 activity of zinc oxide doped TiO₂ nanocrystals: Investigation of bio-medical application by chemical method. Mater Sci Eng C, 74, 325(2017).

[8] D L Gapale, S A Arote, R Y Borse. Mathematical modeling of droplet formation, evaporation, and film growth to study crystallite size and film thickness of spray pyrolysis deposited TiO₂ thin films. e-J Surf Sci Nanotechnol, 16, 419(2018).

[9] A S Hassanien, A A Akl. Optical characteristics of iron oxide thin films prepared by spray pyrolysis technique at different substrate temperatures. Appl Phys A, 124, 752(2018).

[10] K T Ranjit, H Cohen, I Willner. Lanthanide oxide-doped titanium dioxide: Effective photocatalysts for the degradation of organic pollutants. J Mater Sci, 34, 5273(1999).

[11] J Nowotny, C C Sorrell, L R Sheppard. Solar-hydrogen: environmentally safe fuel for the future. Int J Hydrogen Energy, 30, 521(2005).

[12] D A H Hanaor, C C Sorrell. Review of the anatase to rutile phase transformation. J Mater Sci, 46, 855(2011).

[13] D J Reidy, J D Holmes, M A Morris. The critical size mechanism for the anatase to rutile transformation in TiO₂ and doped-TiO₂. J Eur Ceram Soc, 26, 1527(2006).

[14] N Serpone. Is the band gap of pristine TiO₂ narrowed by anion- and cation-doping of titanium dioxide in second-generation photocatalysts. J Phys Chem B, 110, 24287(2006).

[15] V N Nguyen, N K T Nguyen, P H Nguyen. Hydrothermal synthesis of Fe-doped TiO₂ nanostructure photocatalyst. Adv Nat Sci Nanosci Nanotechnol, 2, 035014(2011).

[16] S B Eadi, S Kim, S W Jeong. Novel preparation of Fe doped TiO₂ nanoparticles and their application for gas sensor and photocatalytic degradation. Adv Mater Sci Eng, 2017, 2191659(2017).

[17] R Dholam, N Patel, M Adami. Hydrogen production by photocatalytic water-splitting using Cr- or Fe-doped TiO₂ composite thin films photocatalyst. Int J Hydrogen Energy, 34, 5337(2009).

[18] D Hernández-Rivera, G Rodríguez-Roldán, R Mora-Martínez et al. A capacitive humidity sensor based on an electrospun PVDF/graphene membrane. Sensors, 17, 1009(2017).

[19] G Shukla, S Walia, S Kundu et al. Humidity sensing and breath analyzing applications of TiO₂ slanted nanorod arrays. Sens Actuators A, 301, 111758(2019).

[20] Z Li, A A Haidry, B Gao et al. The effect of Co-doping on the humidity sensing properties of ordered mesoporous TiO₂. Appl Surf Sci, 412, 638(2017).

[21] M Zhang, S Wei, W Ren et al. Development of high sensitivity humidity sensor based on Gray TiO₂/SrTiO₃ composite. Sensors, 17, 1310(2017).

[22] T Ali, P Tripathi, A Azam. Photocatalytic performance of Fe-doped TiO₂ nanoparticles under visible-light irradiation. Mater Res Express, 4, 015022(2017).

[23] X Hou, M Huang, X Wu. First-principles calculations on implanted TiO₂ by 3d transition metal ions. Sci China Ser G, 52, 838(2009).

[24] Z Essalhi, B Hartiti, A Lfakir. Optical properties of TiO₂ Thin films prepared by Sol Gel method. J Mater Environ Sci, 7, 1328(2016).

[25] D L Gapale, S A Arote, B M Palve. Effect of film thickness on humidity sensing of spray deposited TiO₂ thin films. Mater Res Express, 6, 026402(2018).

[26] P B Nair, L V Maneeshya, V B Justinvictor. Evolution of structural and optical properties of photocatalytic Fe doped TiO₂ thin films prepared by RF magnetron sputtering. AIP Conf Proc, 1576, 79(2014).

[27] C S Sebnem, S Corekci, M Cakmak. Structural investigation and electronic band transitions of nanostructured TiO₂ thin films. Cryst Res Technol, 46, 1207(2011).

[28] Y Xu, S Wu, P Wan. Introducing Ti³⁺ defects based on lattice distortion for enhanced visible light photoreactivity in TiO₂ microspheres. RSC Adv, 7, 32461(2017).

[29] D Li, H Song, X Meng et al. Effects of particle size on the structure and photocatalytic performance by alkali-treated TiO₂. Nanomaterials, 10, 546(2020).

[30] A Reetu, S Agarwal et al. Improved dielectric and magnetic properties of Ti modified BiCaFeO₃ multiferroic ceramics. J Appl Phy, 113, 023908(2013).

[31] L Patil, D Suryawanshi, I Pathan. Effect of variation of precursor concentration on structural, microstructural, optical and gas sensing properties of nanocrystalline TiO₂ thin films prepared by spray pyrolysis techniques. Bull Mater Sci, 36, 1153(2013).

[32] Y Hiromi, H Masaru, M Junko. Photocatalytic degradation of organic compounds diluted in water using visible light-responsive metal ion-implanted TiO₂ catalysts: Fe ion-implanted TiO₂. Catal Today, 84, 191(2003).

[33] A R Bally, E N Korobeinikova, P E Schmid et al. Structural and electrical properties of Fe-doped thin films. J Phys D, 31, 1149(1998).

[34] P Traiwatcharanon, K Timsorn, C Wongchoosuk. Flexible room-temperature resistive humidity sensor based on silver nanoparticles. Mater Res Express, 4, 085038(2017).

[35] H Farahani, R Wagiran, M N Hamidon. Humidity sensors principle, mechanism, and fabrication technologies: A comprehensive review. Sensors, 14, 7881(2014).

[36] M Sasikumar, N P Subiramaniyam. Microstructure, electrical and humidity sensing properties of TiO₂/polyaniline nanocomposite films prepared by sol–gel spin coating technique. J Mater Sci - Mater Electron, 29, 7099(2018).

[37] D L Gapale, S A Arote, B M Palve. Influence of precursor solution concentration on structural, optical and humidity sensing properties of spray deposited TiO₂ thin films. J Semicond, 39, 122003(2018).

[38] K Rathi, K Pal. Impact of doping on GO: Fast response–recovery humidity sensor. ACS Omega, 2, 842(2017).

[39] R Keren. Water vapor isotherms and heat of immersion of Na/Ca-montmorillonite systems—I: Homoionic. Clays Clay Miner, 23, 193(1975).

[40] Y Ren, J Yang, Y Ma. Increasing sensing sensitivity of the Fe-α-Fe₂O₃ (104) surface by hydrogenation and the sensing reaction molecule mechanism. Sens Actuators B, 281, 366(2019).

[41] T Morimoto, M Nagao, F Tokuda. Relation between the amounts of chemisorbed and physisorbed water on metal oxides. J Phys Chem, 73, 243(1969).

[42] E Traversa, G Gnappi, A Montenero. Ceramic thin films by sol-gel processing as novel materials for integrated humidity sensors. Sens Actuators B, 31, 59(1996).

[43] N Camaioni, G Casalboremiceli, Y Li. Water activated ionic conduction in cross-linked polyelectrolytes. Sens Actuators B, 134, 230(2008).