{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,6]],"date-time":"2026-02-06T22:15:52Z","timestamp":1770416152008,"version":"3.49.0"},"reference-count":36,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2020,10,29]],"date-time":"2020-10-29T00:00:00Z","timestamp":1603929600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology, Taiwan","doi-asserted-by":"publisher","award":["MOST-108-2221-E-006-196-MY3"],"award-info":[{"award-number":["MOST-108-2221-E-006-196-MY3"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology, Taiwan","doi-asserted-by":"publisher","award":["MOST-108-2221-E-006-215-MY3"],"award-info":[{"award-number":["MOST-108-2221-E-006-215-MY3"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this work, Ga2O3 films were deposited on sapphire substrates using a plasma-enhanced atomic layer deposition system with trimethylgallium precursor and oxygen (O2) plasma. To improve the quality of Ga2O3 films, they were annealed in an O2 ambient furnace system for 15 min at 700, 800, and 900 \u00b0C, respectively. The performance improvement was verified from the measurement results of X-ray diffraction, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy. The optical bandgap energy of the Ga2O3 films decreased with an increase of annealing temperatures. Metal-semiconductor-metal ultraviolet C photodetectors (MSM UVC-PDs) with various Ga2O3 active layers were fabricated and studied in this work. The cut-off wavelength of the MSM UVC-PDs with the Ga2O3 active layers annealed at 800 \u00b0C was 250 nm. Compared with the performance of the MSM UVC-PDs with the as-grown Ga2O3 active layers, the MSM UVC-PDs with the 800 \u00b0C-annealed Ga2O3 active layers under a bias voltage of 5 V exhibited better performances including photoresponsivity of 22.19 A\/W, UV\/visible rejection ratio of 5.98 \u00d7 104, and detectivity of 8.74 \u00d7 1012 cmHz1\/2W\u22121.<\/jats:p>","DOI":"10.3390\/s20216159","type":"journal-article","created":{"date-parts":[[2020,10,29]],"date-time":"2020-10-29T21:21:00Z","timestamp":1604006460000},"page":"6159","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":29,"title":["Investigation of Ga2O3-Based Deep Ultraviolet Photodetectors Using Plasma-Enhanced Atomic Layer Deposition System"],"prefix":"10.3390","volume":"20","author":[{"given":"Shao-Yu","family":"Chu","sequence":"first","affiliation":[{"name":"Department of Photonics, National Cheng Kung University, Tainan 701, Taiwan"}]},{"given":"Meng-Xian","family":"Shen","sequence":"additional","affiliation":[{"name":"Department of Photonics, National Cheng Kung University, Tainan 701, Taiwan"}]},{"given":"Tsung-Han","family":"Yeh","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronic Engineering, Chung Cheng Institute of Technology, National Defense University, Taoyuan 335, Taiwan"}]},{"given":"Chia-Hsun","family":"Chen","sequence":"additional","affiliation":[{"name":"Department of Optometry, Chung Hwa University of Medical Technology, Tainan 701, Taiwan"}]},{"given":"Ching-Ting","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Photonics, National Cheng Kung University, Tainan 701, Taiwan"},{"name":"Department of Electrical Engineering, Yuan Ze University, Taoyuan 320, Taiwan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8493-9442","authenticated-orcid":false,"given":"Hsin-Ying","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Photonics, National Cheng Kung University, Tainan 701, Taiwan"}]}],"member":"1968","published-online":{"date-parts":[[2020,10,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"SDDF04","DOI":"10.7567\/1347-4065\/ab54f0","article-title":"MgZnO\/SiO2\/ZnO metal-semiconductor-metal dual-band UVA and UVB photodetector with different MgZnO thicknesses by RF magnetron sputter","volume":"59","author":"Jheng","year":"2020","journal-title":"Jpn. J. Appl. Phys."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"603","DOI":"10.1016\/j.jff.2018.11.037","article-title":"Mechanisms underlying the protective effects of blueberry extract against ultraviolet radiation in a skin cell co-culture system","volume":"52","author":"Wang","year":"2020","journal-title":"J. Funct. Foods"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1323","DOI":"10.1063\/1.1557325","article-title":"Solar-blind ultraviolet photodetectors based on superlattices of AlN\/AlGa(In)N","volume":"82","author":"Kuryatkov","year":"2003","journal-title":"Appl. Phys. Lett."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"173505","DOI":"10.1063\/1.3002371","article-title":"MgxZn1\u2212xO-based photodetectors covering the whole solar-blind spectrum range","volume":"93","author":"Ju","year":"2008","journal-title":"Appl. Phys. Lett."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"8604","DOI":"10.3390\/s100908604","article-title":"ZnO-Based Ultraviolet Photodetectors","volume":"10","author":"Liu","year":"2010","journal-title":"Sensors"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1016\/j.jallcom.2019.06.224","article-title":"High transmittance beta-Ga2O3 thin films deposited by magnetron sputtering and post-annealing for solar-blind ultraviolet photodetector","volume":"803","author":"Wang","year":"2019","journal-title":"J. Alloys Compd."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"549","DOI":"10.1109\/LPT.2018.2803763","article-title":"Modulated Al2O3-alloyed Ga2O3 materials and deep ultraviolet photodetectors","volume":"30","author":"Lee","year":"2018","journal-title":"IEEE Photon. Technol. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"141106","DOI":"10.1063\/1.4897527","article-title":"Low-threshold stimulated emission at 249 \u2009nm and 256\u2009nm from AlGaN-based multiple-quantum-well lasers grown on sapphire substrates","volume":"105","author":"Li","year":"2014","journal-title":"Appl. Phys. Lett."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2108","DOI":"10.1109\/LPT.2008.2006914","article-title":"Ultraviolet photodetector based on MgxZn1-xO thin films deposited by radio frequency magnetron sputtering","volume":"20","author":"Lee","year":"2008","journal-title":"IEEE Photon. Technol. Lett."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"5561","DOI":"10.1063\/1.1413948","article-title":"Photoluminescence properties of MgxZn1-xO alloy thin films fabricated by the sol-gel deposition method","volume":"90","author":"Zhao","year":"2001","journal-title":"J. Appl. Phys."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"356","DOI":"10.1149\/2.0031707jss","article-title":"Perspective-Opportunities and future directions for Ga2O3","volume":"6","author":"Mastro","year":"2017","journal-title":"ECS J. Solid State Sci. Technol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"011301","DOI":"10.1063\/1.5006941","article-title":"A review of Ga2O3 materials, processing, and devices","volume":"5","author":"Pearton","year":"2018","journal-title":"Appl. Phys. Rev."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"150","DOI":"10.1016\/j.jallcom.2017.11.037","article-title":"High quality beta-Ga2O3 film grown with N2O for high sensitivity solar-blind-ultraviolet photodetector with fast response speed","volume":"735","author":"Zhang","year":"2018","journal-title":"J. Alloys Compd."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"022527","DOI":"10.1063\/1.5064471","article-title":"Solar blind Schottky photodiode based on an MOCVD-grown homoepitaxial \u03b2-Ga2O3 thin film","volume":"7","author":"Alema","year":"2019","journal-title":"APL Mater."},{"key":"ref_15","first-page":"100","article-title":"Toward controlling the carrier density of Si doped Ga2O3 films by pulsed laser deposition","volume":"109","author":"Zhang","year":"2016","journal-title":"Appl. Phys. Lett."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1016\/j.tsf.2017.08.038","article-title":"Characteristics of thulium doped gallium oxide films grown by pulsed laser deposition","volume":"639","author":"Guo","year":"2017","journal-title":"Thin Solid Films"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1016\/j.jallcom.2017.05.077","article-title":"Structural and photoelectrical properties of Ga2O3\/SiC\/Al2O3 multilayers","volume":"717","author":"Huang","year":"2017","journal-title":"J. Alloys Compd."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"060313","DOI":"10.7567\/JJAP.57.060313","article-title":"Demonstration of zero bias responsivity in MBE grown \u03b2-Ga2O3 lateral deep-UV photodetector","volume":"57","author":"Pratiyush","year":"2018","journal-title":"Jpn. J. Appl. Phys."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"928","DOI":"10.1116\/1.1474418","article-title":"Microstructural characterization of radio frequency magnetron sputter-deposited Ga2O3: Mn phosphor thin films","volume":"20","author":"Kim","year":"2002","journal-title":"J. Vac. Sci. Technol. A"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"10335","DOI":"10.1007\/s10853-019-03628-z","article-title":"Improving the production of high-performance solar-blind \u03b2-Ga2O3 photodetectors by controlling the growth pressure","volume":"54","author":"Li","year":"2019","journal-title":"J. Mater. Sci."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Dyndal, K., Zarzycki, A., Andrysiewicz, W., Grochala, D., Marszalek, K., and Rydosz, A. (2020). CuO-Ga2O3 Thin Films as a Gas-Sensitive Material for Acetone Detection. Sensors, 20.","DOI":"10.3390\/s20113142"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"117326","DOI":"10.1016\/j.jlumin.2020.117326","article-title":"Ga2O3-based solar-blind deep ultraviolet light-emitting diodes","volume":"224","author":"Lin","year":"2020","journal-title":"J. Lumin."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"941","DOI":"10.1109\/LPT.2020.3003594","article-title":"Whole metal oxide p-i-n deep ultraviolet light-emitting diodes using i-Ga2O3 active emissive film","volume":"32","author":"Lee","year":"2020","journal-title":"IEEE Photon. Technol. Lett."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"050801","DOI":"10.1116\/1.3609974","article-title":"Plasma-assisted atomic layer deposition basics opportunities and challenges","volume":"29","author":"Profijt","year":"2011","journal-title":"J. Vac. Sci. Technol. A"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"16551","DOI":"10.1039\/C7DT03427J","article-title":"Low temperature growth of gallium oxide thin films via plasma enhanced atomic layer deposition","volume":"46","author":"Rechmann","year":"2017","journal-title":"Dalton Trans."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"562","DOI":"10.1186\/1556-276X-7-562","article-title":"Valence band offset of beta-Ga2O3\/wurtzite GaN heterostructure measured by X-ray photoelectron spectroscopy","volume":"7","author":"Wei","year":"2012","journal-title":"Nanoscale Res. Lett."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"483","DOI":"10.1007\/s13391-017-7072-y","article-title":"Decrease of oxygen vacancy by Zn-doped for improving solar-blind photoelectric performance in \u03b2-Ga2O3 thin films","volume":"13","author":"Guo","year":"2017","journal-title":"Electron. Mater. Lett."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1016\/j.tsf.2016.07.074","article-title":"Growth and morphology control of beta-Ga2O3 nanostructures by atmospheric-pressure CVD","volume":"620","author":"Terasako","year":"2016","journal-title":"Thin Solid Films"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"112141","DOI":"10.1016\/j.sna.2020.112141","article-title":"Development and characterization of MSM UV photodetector based on gallium oxide nanostructures","volume":"312","author":"Jubu","year":"2020","journal-title":"Sens. Actuator A-Phys."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"13554","DOI":"10.1364\/OE.23.013554","article-title":"High gain Ga2O3 solar-blind photodetectors realized via a carrier multiplication process","volume":"23","author":"Hu","year":"2015","journal-title":"Opt. Express"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"993","DOI":"10.1109\/LPT.2018.2826560","article-title":"Arrays of solar-blind ultraviolet photodetector based on beta-Ga2O3 epitaxial thin films","volume":"30","author":"Peng","year":"2018","journal-title":"IEEE Photon. Technol. Lett."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1123","DOI":"10.1021\/acsphotonics.7b01486","article-title":"High responsivity beta-Ga2O3 metal-semiconductor-metal solar-blind photodetectors with ultraviolet transparent graphene electrodes","volume":"5","author":"Oh","year":"2018","journal-title":"ACS Photon."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"100193","DOI":"10.1016\/j.mtphys.2020.100193","article-title":"Vertical \u03b1\/\u03b2-Ga2O3 phase junction nanorods array with graphene silver nanowire hybrid conductive electrode for high-performance self-powered solar-blind photodetectors","volume":"12","author":"Wu","year":"2020","journal-title":"Mater. Today Phys."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1007\/s11664-019-07706-5","article-title":"Hydrothermally-grown TiO2 thin film-based metal-semiconductor-metal UV photodetector","volume":"49","author":"Kumbhar","year":"2020","journal-title":"J. Electron. Mater."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"15659","DOI":"10.1007\/s10854-020-04130-y","article-title":"Ultraviolet photodetector fabricated using laser sintering method grown Mg0.2Zn0.8O film","volume":"31","author":"Wang","year":"2020","journal-title":"J. Mater. Sci.-Mater. Electron."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"422","DOI":"10.1016\/j.apsusc.2019.03.110","article-title":"ZnO ultraviolet photodetectors with an extremely high detectivity and short response time","volume":"481","author":"Zheng","year":"2019","journal-title":"Appl. Surf. Sci."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/21\/6159\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:26:18Z","timestamp":1760178378000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/21\/6159"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,10,29]]},"references-count":36,"journal-issue":{"issue":"21","published-online":{"date-parts":[[2020,11]]}},"alternative-id":["s20216159"],"URL":"https:\/\/doi.org\/10.3390\/s20216159","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,10,29]]}}}