{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,3]],"date-time":"2026-03-03T12:08:07Z","timestamp":1772539687843,"version":"3.50.1"},"reference-count":40,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2021,2,3]],"date-time":"2021-02-03T00:00:00Z","timestamp":1612310400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Herein, the fabrication of a novel highly sensitive and fast hydrogen (H2) gas sensor, based on the Ta2O5 Schottky diode, is described. First, Ta2O5 thin films are deposited on silicon carbide (SiC) and silicon (Si) substrates via a radio frequency (RF) sputtering method. Then, Pd and Ni are respectively deposited on the front and back of the device. The deposited Pd serves as a H2 catalyst, while the Ni functions as an Ohmic contact. The devices are then tested under various concentrations of H2 gas at operating temperatures of 300, 500, and 700 \u00b0C. The results indicate that the Pd\/Ta2O5 Schottky diode on the SiC substrate exhibits larger concentration and temperature sensitivities than those of the device based on the Si substrate. In addition, the optimum operating temperature of the Pd\/Ta2O5 Schottky diode for use in H2 sensing is shown to be about 300 \u00b0C. At this optimum temperature, the dynamic responses of the sensors towards various concentrations of H2 gas are then examined under a constant bias current of 1 mA. The results indicate a fast rise time of 7.1 s, and a decay of 18 s, for the sensor based on the SiC substrate.<\/jats:p>","DOI":"10.3390\/s21041042","type":"journal-article","created":{"date-parts":[[2021,2,3]],"date-time":"2021-02-03T20:31:51Z","timestamp":1612384311000},"page":"1042","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Highly Fast Response of Pd\/Ta2O5\/SiC and Pd\/Ta2O5\/Si Schottky Diode-Based Hydrogen Sensors"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8767-3205","authenticated-orcid":false,"given":"Muhammad","family":"Hussain","sequence":"first","affiliation":[{"name":"Department of Nanotechnology and Advanced Materials Engineering and HMC, Sejong University, Seoul 05006, Korea"}]},{"given":"Woonyoung","family":"Jeong","sequence":"additional","affiliation":[{"name":"Department of Nanotechnology and Advanced Materials Engineering and HMC, Sejong University, Seoul 05006, Korea"}]},{"given":"Il-Suk","family":"Kang","sequence":"additional","affiliation":[{"name":"National Nanofab Center, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4950-757X","authenticated-orcid":false,"given":"Kyeong-Keun","family":"Choi","sequence":"additional","affiliation":[{"name":"NINT (National Institute for Nanomaterials Technology), Pohang University of Science and Technology, Pohang 37673, Korea"}]},{"given":"Syed Hassan Abbas","family":"Jaffery","sequence":"additional","affiliation":[{"name":"Department of Nanotechnology and Advanced Materials Engineering and HMC, Sejong University, Seoul 05006, Korea"}]},{"given":"Asif","family":"Ali","sequence":"additional","affiliation":[{"name":"Department of Nanotechnology and Advanced Materials Engineering and HMC, Sejong University, Seoul 05006, Korea"}]},{"given":"Tassawar","family":"Hussain","sequence":"additional","affiliation":[{"name":"Department of Nanotechnology and Advanced Materials Engineering and HMC, Sejong University, Seoul 05006, Korea"}]},{"given":"Muhammad","family":"Ayaz","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, Semyung University, Chungcheongbuk-do 27136, Korea"}]},{"given":"Sajjad","family":"Hussain","sequence":"additional","affiliation":[{"name":"Department of Nanotechnology and Advanced Materials Engineering and HMC, Sejong University, Seoul 05006, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1397-212X","authenticated-orcid":false,"given":"Jongwan","family":"Jung","sequence":"additional","affiliation":[{"name":"Department of Nanotechnology and Advanced Materials Engineering and HMC, Sejong University, Seoul 05006, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2021,2,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"867","DOI":"10.1021\/cm052256f","article-title":"Nearly monodisperse Cu2O and CuO nanospheres: Preparation and applications for sensitive gas sensors","volume":"18","author":"Zhang","year":"2006","journal-title":"Chem. Mater."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"508","DOI":"10.1016\/j.snb.2006.03.004","article-title":"Highly sensitive gas sensors based on hollow SnO2 spheres prepared by carbon sphere template method","volume":"120","author":"Caihong","year":"2007","journal-title":"Sens. Actuators B Chem."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"085203","DOI":"10.1088\/0957-4484\/20\/8\/085203","article-title":"Multifunctional CuO nanowire devices: P-type field effect transistors and CO gas sensors","volume":"20","author":"Liao","year":"2009","journal-title":"Nanotechnology"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"667","DOI":"10.1021\/nl050082v","article-title":"Enhanced gas sensing by individual SnO2 nanowires and nanobelts functionalized with Pd catalyst particles","volume":"5","author":"Kolmakov","year":"2005","journal-title":"Nano Lett."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"4303","DOI":"10.1016\/j.matlet.2008.07.012","article-title":"Preparation and gas sensing properties of p-type La-Bi-Fe-O nanorods","volume":"62","author":"Ruan","year":"2008","journal-title":"Mater. Lett."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1007\/s10832-008-9555-6","article-title":"Size-dependent photovoltaic property in hollow hemisphere array based dye-sensitized solar cells","volume":"24","author":"Yang","year":"2010","journal-title":"J. Electroceram."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2623","DOI":"10.1021\/nn900126k","article-title":"Hollow ZnO nanofibers fabricated using electrospun polymer templates and their electronic transport properties","volume":"3","author":"Choi","year":"2009","journal-title":"ACS Nano"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Constantinoiu, I., and Viespe, C. (2020). Development of Pd\/TiO2 Porous Layers by Pulsed Laser Deposition for Surface Acoustic Wave H2 Gas Sensor. Nanomaterials, 10.","DOI":"10.3390\/nano10040760"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"270","DOI":"10.1016\/j.snb.2005.09.013","article-title":"Highly sensitive hydrogen sulphide sensors operable at room temperature","volume":"115","author":"Sen","year":"2006","journal-title":"Sens. Actuators B Chem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1107","DOI":"10.1016\/j.ijhydene.2010.10.011","article-title":"Highly sensitive hydrogen sensors based on co-sputtered platinum-activated tungsten oxide films","volume":"36","author":"Zhang","year":"2011","journal-title":"Int. J. Hydrog. Energy"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"901","DOI":"10.1007\/s11581-014-1140-1","article-title":"A review of mixed-potential type zirconia-based gas sensors","volume":"20","author":"Miura","year":"2014","journal-title":"Ionics"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"22746","DOI":"10.1016\/j.ijhydene.2018.10.101","article-title":"Hydrogen gas sensor based on mesoporous In2O3 with fast response\/recovery and ppb level detection limit","volume":"43","author":"Li","year":"2018","journal-title":"Int. J. Hydrog. Energy"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"984","DOI":"10.1016\/j.snb.2017.07.093","article-title":"Ultra-high sensitive and selective H2 gas sensor manifested by interface of n\u2013n heterostructure of CeO2-SnO2 nanoparticles","volume":"254","author":"Motaung","year":"2018","journal-title":"Sens. Actuators B Chem."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"795","DOI":"10.1016\/j.proeng.2014.11.677","article-title":"Semiconductor metal oxides as hydrogen gas sensors","volume":"87","author":"Phanichphant","year":"2014","journal-title":"Procedia Eng."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"4526","DOI":"10.1016\/j.ijhydene.2011.12.004","article-title":"Fast and highly-sensitive hydrogen sensing of Nb2O5 nanowires at room temperature","volume":"37","author":"Wang","year":"2012","journal-title":"Int. J. Hydrog. Energy"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"110","DOI":"10.1016\/j.apsusc.2012.09.061","article-title":"Sputtered TiO2 thin films with NiO additives for hydrogen detection","volume":"269","author":"Kosc","year":"2013","journal-title":"Appl. Surf. Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"162","DOI":"10.1016\/j.snb.2010.09.027","article-title":"H2 gas sensor performance of NiO at high temperatures in gas mixtures","volume":"151","author":"Steinebach","year":"2010","journal-title":"Sens. Actuators B Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1016\/j.cattod.2004.06.049","article-title":"Preferential oxidation of CO in H2 over CuO-CeO2 catalysts","volume":"93","author":"Liu","year":"2004","journal-title":"Catal. Today"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"873","DOI":"10.1016\/j.snb.2014.06.124","article-title":"Mesoporous Co3O4 nanoneedle arrays for high-performance gas sensor","volume":"203","author":"Wen","year":"2014","journal-title":"Sens. Actuators B Chem."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Mohd Chachuli, S.A., Hamidon, M.N., Mamat, M., Ertugrul, M., and Abdullah, N.H. (2018). A hydrogen gas sensor based on TiO2 nanoparticles on alumina substrate. Sensors, 18.","DOI":"10.3390\/s18082483"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"987","DOI":"10.1016\/j.matchemphys.2012.02.002","article-title":"Design and fabrication of micro hydrogen gas sensors using palladium thin film","volume":"133","author":"Yoon","year":"2012","journal-title":"Mater. Chem. Phys."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1021\/nn800593m","article-title":"Practical chemical sensors from chemically derived graphene","volume":"3","author":"Fowler","year":"2009","journal-title":"ACS Nano"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"652","DOI":"10.1038\/nmat1967","article-title":"Detection of individual gas molecules adsorbed on graphene","volume":"6","author":"Schedin","year":"2007","journal-title":"Nat. Mater."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"185504","DOI":"10.1088\/0957-4484\/20\/18\/185504","article-title":"Improving gas sensing properties of graphene by introducing dopants and defects: A first-principles study","volume":"20","author":"Zhang","year":"2009","journal-title":"Nanotechnology"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1366","DOI":"10.1109\/LED.2015.2492580","article-title":"Density-functional calculation of methane adsorption on graphenes","volume":"36","author":"Chen","year":"2015","journal-title":"IEEE Electron. Device Lett."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"575","DOI":"10.1016\/j.apsusc.2017.10.084","article-title":"High selective gas detection for small molecules based on germanium selenide monolayer","volume":"433","author":"Liu","year":"2018","journal-title":"Appl. Surf. Sci."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"10078","DOI":"10.1039\/C5NR01924A","article-title":"Hydrogen gas sensor based on metal oxide nanoparticles decorated graphene transistor","volume":"7","author":"Zhang","year":"2015","journal-title":"Nanoscale"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"3707","DOI":"10.1016\/j.electacta.2010.10.078","article-title":"Hydrogen sensor based on a graphene\u2013palladium nanocomposite","volume":"56","author":"Lange","year":"2011","journal-title":"Electrochim. Acta"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2675","DOI":"10.1021\/jz501188k","article-title":"Phosphorene as a superior gas sensor: Selective adsorption and distinct I\u2013V response","volume":"5","author":"Kou","year":"2014","journal-title":"J. Phys. Chem. Lett."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"686","DOI":"10.1016\/j.snb.2017.05.028","article-title":"MoS2 gas sensor functionalized by Pd for the detection of hydrogen","volume":"250","author":"Baek","year":"2017","journal-title":"Sens. Actuators B Chem."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1016\/j.apsusc.2018.05.148","article-title":"Two-dimensional WS2-based nanosheets modified by Pt quantum dots for enhanced room-temperature NH3 sensing properties","volume":"455","author":"Ouyang","year":"2018","journal-title":"Appl. Surf. Sci."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"195501","DOI":"10.1088\/0957-4484\/27\/19\/195501","article-title":"High-performance flexible hydrogen sensor made of WS2 nanosheet\u2013Pd nanoparticle composite film","volume":"27","author":"Kuru","year":"2016","journal-title":"Nanotechnology"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1603","DOI":"10.1021\/acssensors.9b00303","article-title":"Two-dimensional vanadium carbide MXene for gas sensors with ultrahigh sensitivity toward nonpolar gases","volume":"4","author":"Lee","year":"2019","journal-title":"ACS Sens."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1016\/j.snb.2010.09.059","article-title":"Advances of SiC-based MOS capacitor hydrogen sensors for harsh environment applications","volume":"151","author":"Soo","year":"2010","journal-title":"Sens. Actuators B Chem."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1016\/j.proeng.2010.09.069","article-title":"Hydrogen gas sensing properties of Pt\/Ta2O5 Schottky diodes based on Si and SiC substrates","volume":"5","author":"Yu","year":"2010","journal-title":"Procedia Eng."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1794","DOI":"10.3938\/jkps.63.1794","article-title":"Pd\/Ta2O5\/SiC Schottky-diode hydrogen sensors formed by using rapid thermal oxidation of Ta thin films","volume":"63","author":"Joo","year":"2013","journal-title":"J. Korean Phys. Soc."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"13575","DOI":"10.3390\/s131013575","article-title":"Silicon carbide-based hydrogen gas sensors for high-temperature applications","volume":"13","author":"Kim","year":"2013","journal-title":"Sensors"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"19810","DOI":"10.1016\/j.ijhydene.2018.08.187","article-title":"Capacitance response characteristics of hydrogen sensor with tantalum oxide dielectric layer","volume":"43","author":"Kim","year":"2018","journal-title":"Int. J. Hydrog. Energy"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1228","DOI":"10.1116\/1.580600","article-title":"Comparison of interfacial and electronic properties of annealed Pd\/SiC and Pd\/SiO2\/SiC Schottky diode sensors","volume":"15","author":"Chen","year":"1997","journal-title":"J. Vac. Sci. Technol. A"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1016\/j.apsusc.2003.09.040","article-title":"XPS study of N2 annealing effect on thermal Ta2O5 layers on Si","volume":"225","author":"Atanassova","year":"2004","journal-title":"Appl. Surf. Sci."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/4\/1042\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T05:19:34Z","timestamp":1760159974000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/4\/1042"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,2,3]]},"references-count":40,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2021,2]]}},"alternative-id":["s21041042"],"URL":"https:\/\/doi.org\/10.3390\/s21041042","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,2,3]]}}}