This work presents the effect of magnesium (Mg) doping on the sensing properties of tin dioxide (SnO2) thin films. Mg-doped SnO2 films were prepared via a spray pyrolysis method using three doping concentrations (0.8 at.%, 1.2 at.%, and 1.6 at.%) and the sensing responses were obtained at a comparatively low operating temperature (160 °C) compared to other gas sensitive materials in the literature. The morphological, structural and chemical composition analysis of the doped films show local lattice disorders and a proportional decrease in the average crystallite size as the Mg-doping level increases. These results also indicate an excess of Mg (in the samples prepared with 1.6 at.% of magnesium) which causes the formation of a secondary magnesium oxide phase. The films are tested towards three volatile organic compounds (VOCs), including ethanol, acetone, and toluene. The gas sensing tests show an enhancement of the sensing properties to these vapors as the Mg-doping level rises. This improvement is particularly observed for ethanol and, thus, the gas sensing analysis is focused on this analyte. Results to 80 ppm of ethanol, for instance, show that the response of the 1.6 at.% Mg-doped SnO2 film is four times higher and 90 s faster than that of the 0.8 at.% Mg-doped SnO2 film. This enhancement is attributed to the Mg-incorporation into the SnO2 cell and to the formation of MgO within the film. These two factors maximize the electrical resistance change in the gas adsorption stage, and thus, raise ethanol sensitivity.

CEITEC Central European Institute of Technology Brno University of Technology 61200 Brno Czech Republic

Electronic Materials Study for Medical Applications Laboratory Electronic Department Science and Technology Faculty Frères Mentouri University 25000 Constantine Algeria

Instituto de Microelectrónica de Barcelona Campus UAB 08193 Bellaterra Spain

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Schütze A., Baur T., Leidinger M., Reimringer W., Jung R., Conrad T., Sauerwald T. Highly Sensitive and Selective VOC Sensor Systems Based on Semiconductor Gas Sensors: How to? Environment. 2017;4:20. doi: 10.3390/environments4010020. DOI

Yoon J.-W., Lee J.-H. Toward breath analysis on a chip for disease diagnosis using semiconductor-based chemiresistors: Recent progress and future perspectives. LAB CHIP. 2017;17:3537–3557. doi: 10.1039/C7LC00810D. PubMed DOI

Kumar M., Gupta A.K., Kumar D. Mg-doped TiO2 thin films deposited by low cost technique for CO gas monitoring. Ceram. Int. 2016;42:405–410. doi: 10.1016/j.ceramint.2015.08.124. DOI

Vallejos S., Gràcia I., Lednický T., Vojkuvka L., Figueras E., Hubálek J., Cané C. Highly hydrogen sensitive micromachined sensors based on aerosol-assisted chemical vapor deposited ZnO rods. Sens. Actuators B Chem. 2018;268:15–21. doi: 10.1016/j.snb.2018.04.033. DOI

Vallejos S., Selina S., Annanouch F.E., Gràcia I., Llobet E., Blackman C. Aerosol assisted chemical vapour deposition of gas sensitive SnO2 and Au-functionalised SnO2 nanorods via a non-catalysed vapour solid (VS) mechanism. Sci. Rep. 2016;6:28464. doi: 10.1038/srep28464. PubMed DOI PMC

Vallejos S., Gràcia I., Figueras E., Cané C. Nanoscale heterostructures based on Fe2O3@ WO3-x nanoneedles and their direct integration into flexible transducing platforms for toluene sensing. ACS Appl. Mater. Interfaces. 2015;7:18638–18649. doi: 10.1021/acsami.5b05081. PubMed DOI

Lou Z., Deng J., Wang L., Wang L., Fei T., Zhang T. Toluene and ethanol sensing performances of pristine and PdO-decorated flower-like ZnO structures. Sens. Actuators B Chem. 2013;176:323–329. doi: 10.1016/j.snb.2012.09.027. DOI

Fu J., Zhao C., Zhang J., Peng Y., Xie E. Enhanced gas sensing performance of electrospun Pt-functionalized NiO nanotubes with chemical and electronic sensitization. ACS Appl. Mater. Interfaces. 2013;5:7410–7416. doi: 10.1021/am4017347. PubMed DOI

Tomić M., Šetka M., Chmela O., Gràcia I., Figueras E., Cané C., Vallejos S. Cerium Oxide-Tungsten Oxide Core-Shell Nanowire-Based Microsensors Sensitive to Acetone. Biosensors. 2018;8:116. doi: 10.3390/bios8040116. PubMed DOI PMC

Zhang Q., Zhou Q., Lu Z., Wei Z., Xu L., Gui Y. Recent advances of SnO2-based sensors for detecting fault characteristic gases extracted from power transformer oil. Front. Chem. 2018;6:364. doi: 10.3389/fchem.2018.00364. PubMed DOI PMC

Belmonte J.C., Manzano J., Arbiol J., Cirera A., Puigcorbe J., Vila A., Sabate N., Gracia I., Cane C., Morante J. Micromachined twin gas sensor for CO and O2 quantification based on catalytically modified nano-SnO2. Sens. Actuators B Chem. 2006;114:881–892. doi: 10.1016/j.snb.2005.08.007. DOI

Liu S., Sun Q., Wang J., Hou H. Charge imbalance induced oxygen-adsorption enhances the gas-sensing properties of Al-doped SnO2 powders. J. Phys. Chem. Solids. 2019;124:163–168. doi: 10.1016/j.jpcs.2018.09.017. DOI

Kang J.-g., Park J.-S., Lee H.-J. Pt-doped SnO2 thin film based micro gas sensors with high selectivity to toluene and HCHO. Sens. Actuators B Chem. 2017;248:1011–1016. doi: 10.1016/j.snb.2017.03.010. DOI

Liang Y.-C., Lee C.-M., Lo Y.-J. Reducing gas-sensing performance of Ce-doped SnO2 thin films through a cosputtering method. RSC Adv. 2017;7:4724–4734. doi: 10.1039/C6RA25853K. DOI

Li W., Ma S., Li Y., Li X., Wang C., Yang X., Cheng L., Mao Y., Luo J., Gengzang D. Preparation of Pr-doped SnO2 hollow nanofibers by electrospinning method and their gas sensing properties. J. Alloy. Compd. 2014;605:80–88. doi: 10.1016/j.jallcom.2014.03.182. DOI

Guan Y., Wang D., Zhou X., Sun P., Wang H., Ma J., Lu G. Hydrothermal preparation and gas sensing properties of Zn-doped SnO2 hierarchical architectures. Sens. Actuators B Chem. 2014;191:45–52. doi: 10.1016/j.snb.2013.09.002. DOI

Amin M., Shah N.A., Bhatti A.S., Malik M.A. Effects of Mg doping on optical and CO gas sensing properties of sensitive ZnO nanobelts. CrystEngComm. 2014;16:6080–6088. doi: 10.1039/C4CE00153B. DOI

Goudarzi S., Khojier K. Role of substrate temperature on the ammonia gas sensing performance of Mg-doped ZnO thin films deposited by spray pyrolysis technique: Application in breath analysis devices. Appl. Phys. A. 2018;124:601. doi: 10.1007/s00339-018-2020-8. DOI

Vinoth E., Gowrishankar S., Gopalakrishnan N. Effect of Mg doping in the gas-sensing performance of RF-sputtered ZnO thin films. Appl. Phys. A. 2018;124:433. doi: 10.1007/s00339-018-1852-6. DOI

Karthick K., Srinivasan D., Christopher J.B. Fabrication of highly c-axis Mg doped ZnO on c-cut sapphire substrate by rf sputtering for hydrogen sensing. J. Mater. Sci-Mater. Elec. 2017;28:11979–11986. doi: 10.1007/s10854-017-7007-2. DOI

Kwak C.-H., Woo H.-S., Abdel-Hady F., Wazzan A., Lee J.-H. Vapor-phase growth of urchin-like Mg-doped ZnO nanowire networks and their application to highly sensitive and selective detection of ethanol. Sens. Actuators B Chem. 2016;223:527–534. doi: 10.1016/j.snb.2015.09.120. DOI

Jo Y.-M., Lee C.-S., Wang R., Park J.-S., Lee J.-H. Highly sensitive and selective ethanol sensors using magnesium doped indium oxide hollow spheres. J. Korean Ceram. Soc. 2017;54:303–307. doi: 10.4191/kcers.2017.54.4.01. DOI

He H., Xie Z., Li Q., Niu H. On the possibility of p-type doping of SnO2 with Mg: A first-principles study. J. Comput. Mater. Sci. 2015;101:62–65. doi: 10.1016/j.commatsci.2015.01.022. DOI

Khatami S.M.N. Ph.D. Thesis. University of Central Florida; Orlando, FL, USA: 2014. [(accessed on 11 March 2020)]. Modeling and Spray Pyrolysis Processing of Mixed Metal Oxide Nano-Composite Gas Sensor Films. Available online: http://purl.fcla.edu/fcla/etd/CFE0005817.

Falcony C., Aguilar-Frutis M.A., García-Hipólito M. Spray pyrolysis technique; high-K dielectric films and luminescent materials: A review. Micromachines. 2018;9:414. doi: 10.3390/mi9080414. PubMed DOI PMC

Touidjen N.H., Bendahmane B., Lamri Zeggar M., Mansour F., Aida M. SnO2 thin film synthesis for organic vapors sensing at ambient temperature. Sens. Biosensing Res. 2016;11:52. doi: 10.1016/j.sbsr.2016.11.001. DOI

Bendahmane B., Touidjen N.H., Mansour F. Characterization of SnO2 Thin Films Fabricated by Chemical Spray Pyrolysis; Proceedings of the International Conference on Advanced Electrical Engineering (ICAEE); Algiers, Algeria. 19–21 November 2019; IEEE; 2020. pp. 1–6. DOI

Vallejos S., Grácia I., Chmela O., Figueras E., Hubálek J., Cané C. Chemoresistive micromachined gas sensors based on functionalized metal oxide nanowires: Performance and reliability. Sens. Actuators B Chem. 2016;235:525–534. doi: 10.1016/j.snb.2016.05.102. DOI

Shajira P., Bushiri M.J., Nair B.B., Prabhu V.G. Energy band structure investigation of blue and green light emitting Mg doped SnO2 nanostructures synthesized by combustion method. J. Lumin. 2014;145:425–429. doi: 10.1016/j.jlumin.2013.07.073. DOI

Mazumder N., Bharati A., Saha S., Sen D., Chattopadhyay K. Effect of Mg doping on the electrical properties of SnO2 nanoparticles. Curr. Appl. Phys. 2012;12:975–982. doi: 10.1016/j.cap.2011.12.022. DOI

Papadopoulos N., Tsakiridis P., Hristoforou E. Structural and electrical properties of undoped SnO2 films developed by a low cost CVD technique with two different methods: Comparative study. [(accessed on 11 March 2020)];J. Opt. Adv. Mat. 2005 7:2693–2706. Available online: https://dspace.lib.ntua.gr/xmlui/handle/123456789/16827.

Kwoka M., Ottaviano L., Passacantando M., Santucci S., Czempik G., Szuber J. XPS study of the surface chemistry of L-CVD SnO2 thin films after oxidation. Thin Solid Films. 2005;490:36–42. doi: 10.1016/j.tsf.2005.04.014. DOI

Aragón F.H., Gonzalez I., Coaquira J.A., Hidalgo P., Brito H.F., Ardisson J.D., Macedo W.A., Morais P.C. Structural and surface study of praseodymium-doped SnO2 nanoparticles prepared by the polymeric precursor method. J. Phys. Chem. C. 2015;119:8711–8717. doi: 10.1021/acs.jpcc.5b00761. DOI

Huang Q., Li X., Liu T., Wu H., Liu X., Feng Q., Liu Y. Enhanced SaOS-2 cell adhesion, proliferation and differentiation on Mg-incorporated micro/nano-topographical TiO2 coatings. Appl. Surf. Sci. 2018;447:767–776. doi: 10.1016/j.apsusc.2018.04.095. DOI

Zhou Y., Peng J., Wang M., Mo J., Deng C., Zhu M. Tribochemical Behavior of Pure Magnesium During Sliding Friction. Metals. 2019;9:311. doi: 10.3390/met9030311. DOI

Dubecký F., Kindl D., Hubík P., Mičušík M., Dubecký M., Boháček P., Vanko G., Gombia E., Nečas V., Mudroň J. A comparative study of Mg and Pt contacts on semi-insulating GaAs: Electrical and XPS characterization. Appl. Surf. Sci. 2017;395:131–135. doi: 10.1016/j.apsusc.2016.04.176. DOI

Kaur H., Bhatti H.S., Singh K. Europium doping effect on 3D flower-like SnO2 nanostructures: Morphological changes, photocatalytic performance and fluorescence detection of heavy metal ion contamination in drinking water. RSC Adv. 2019;9:37450–37466. doi: 10.1039/C9RA03405F. PubMed DOI PMC

Jayanthi K., Chawla S., Sood K., Chhibara M., Singh S. Dopant induced morphology changes in ZnO nanocrystals. Appl. Surf. Sci. 2009;255:5869–5875. doi: 10.1016/j.apsusc.2009.01.032. DOI

Nithyavathy N., Arunmetha S., Vinoth M., Sriram G., Rajendran V. Fabrication of Nanocomposites of SnO2 and MgAl2O4 for Gas Sensing Applications. J. Electron. Mater. 2016;45:2193–2205. doi: 10.1007/s11664-015-4261-z. DOI

Xu H., Ju D., Chen Z., Han R., Zhai T., Yu H., Liu C., Wu X., Wang J., Cao B. A novel hetero-structure sensor based on Au/Mg-doped TiO2/SnO2 nanosheets directly grown on Al2O3 ceramic tubes. Sens. Actuators B Chem. 2018;273:328–335. doi: 10.1016/j.snb.2018.06.055. DOI

Khoang N.D., Van Duy N., Hoa N.D., Van Hieu N. Design of SnO2/ZnO hierarchical nanostructures for enhanced ethanol gas-sensing performance. Sens. Actuators B Chem. 2012;174:594–601. doi: 10.1016/j.snb.2012.07.118. DOI

Tian J., Wang J., Hao Y., Du H., Li X. Toluene sensing properties of porous Pd-loaded flower-like SnO2 microspheres. Sens. Actuators B Chem. 2014;202:795–802. doi: 10.1016/j.snb.2014.05.048. DOI

Wang S., Wang Y., Zhang H., Gao X., Yang J., Wang Y. Fabrication of porous α-Fe2O3 nanoshuttles and their application for toluene sensors. RSC Adv. 2014;4:30840–30849. doi: 10.1039/C4RA03743J. DOI

Wang L., Deng J., Lou Z., Zhang T. Nanoparticles-assembled Co3O4 nanorods p-type nanomaterials: One-pot synthesis and toluene-sensing properties. Sens. Actuators B Chem. 2014;201:1–6. doi: 10.1016/j.snb.2014.04.074. DOI

Thomas B., Skariah B. Spray deposited Mg-doped SnO2 thin film LPG sensor: XPS and EDX analysis in relation to deposition temperature and doping. J. Alloy. Compd. 2015;625:231–240. doi: 10.1016/j.jallcom.2014.11.092. DOI

Barsan N., Weimar U. Conduction model of metal oxide gas sensors. J. Electroceram. 2001;7:143–167. doi: 10.1023/A:1014405811371. DOI

Lenaerts S., Roggen J., Maes G. FT-IR characterization of tin dioxide gas sensor materials under working conditions. Spectrochim. Acta A. 1995;51:883–894. doi: 10.1016/0584-8539(94)01216-4. DOI

Sinha M., Mahapatra R., Mondal B., Maruyama T., Ghosh R. Ultrafast and reversible gas-sensing properties of ZnO nanowire arrays grown by hydrothermal technique. J. Phys. Chem. C. 2016;120:3019–3025. doi: 10.1021/acs.jpcc.5b11012. DOI

Xu C., Tamaki J., Miura N., Yamazoe N. Grain size effects on gas sensitivity of porous SnO2-based elements. Sens. Actuators B Chem. 1991;3:147–155. doi: 10.1016/0925-4005(91)80207-Z. DOI

Kohl D. The role of noble metals in the chemistry of solid-state gas sensors. Sens. Actuators B Chem. 1990;1:158–165. doi: 10.1016/0925-4005(90)80193-4. DOI

Miller D.R., Akbar S.A., Morris P.A. Nanoscale metal oxide-based heterojunctions for gas sensing: A review. Sens. Actuators B Chem. 2014;204:250–272. doi: 10.1016/j.snb.2014.07.074. DOI

Ederth J., Smulko J., Kish L.B., Heszler P., Granqvist C.G. Comparison of classical and fluctuation-enhanced gas sensing with PdxWO3 nanoparticle films. Sens. Actuators B Chem. 2006;113:310–315. doi: 10.1016/j.snb.2005.03.009. DOI

VOCs Sensing by Metal Oxides, Conductive Polymers, and Carbon-Based Materials