(12) United States Patent (10) Patent No.: US 9.270,084 B2 Zhou Et Al

US009270084B2

(12) United States Patent (10) Patent No.: US 9.270,084 B2 Zhou et al. (45) Date of Patent: Feb. 23, 2016

(54) CERIUM DOPED MAGNESIUM BARIUM USPC ...... 252/301.5; 204/192.1, 298.01, 298.16, TUNGSTATE LUMINESCENT THIN FILM, 204/214 VT, 192.26, 298.02, 98.16, 298.13; MANUFACTURING METHOD AND 313/527, 503, 502; 250/214 VT APPLICATION THEREOF See application file for complete search history. (75) Inventors: Mingjie Zhou, Shenzhen (CN); Ping Wang, Shenzhen (CN); Jixing Chen, (56) References Cited Shenzhen (CN); Hui Huang, Shenzhen U.S. PATENT DOCUMENTS (CN) (73) Assignee: Ocean's King Lighting Science & 3,257,327 A 6, 1966 Kurt Technology Co., Ltd. (CN) 3,338,841. A * 8, 1967 Brixner ...... 252/3014 R (*) Notice: Subject to any disclaimer, the term of this (Continued) patent is extended or adjusted under 35 U.S.C. 154(b) by 158 days. FOREIGN PATENT DOCUMENTS (21) Appl. No.: 14/130,228 CN 1865537 A 11, 2006 (22) PCT Filed: Jun. 28, 2011 CN 101368258 2, 2009 (Continued) (86). PCT No.: PCT/CN2011/076467 OTHER PUBLICATIONS S371 (c)(1), (2), (4) Date: Jan. 30, 2014 Machine translation of CN 102791052 A, printed Jul. 30, 2015.* (Continued) (87) PCT Pub. No.: WO2013/000117 PCT Pub. Date: Jan. 3, 2013 Primary Examiner — Matthew E Hoban (65) Prior Publication Data Assistant Examiner — Lynne Edmondson (74) Attorney, Agent, or Firm — Fox Rothschild LLP: US 2014/0145114A1 May 29, 2014 Jianming J. Hao (51) Int. Cl. (57) ABSTRACT C09K II/77 (2006.01) C23C I4/34 (2006.01) Cerium doped magnesium barium tungstate luminescent thin (Continued) film, manufacturing method and application thereofare pro (52) U.S. Cl. vided, said method for manufacturing cerium doped magne CPC ...... HOIS 5/3018 (2013.01); C09K II/7718 sium barium tungstate luminescent thin film comprises the following steps: mixing MgO, BaO, WO, and CeO, sinter (2013.01); C09K II/7768 (2013.01); C23C ing for forming Sputtering target, forming the precursor of 14/081 (2013.01); C23C 14/35 (2013.01); cerium doped magnesium barium tungstate luminescent thin H05B33/14 (2013.01) film by magnetron Sputtering, annealing the precursor of (58) Field of Classification Search cerium doped magnesium barium tungstate luminescent thin CPC ...... C09K11/682: C09K11/7718; C09K film, and then forming cerium doped magnesium barium 11/7768; C09K11/68; C09K11/7708; C09K tungstate luminescent thin film. Said cerium doped magne 11/7722; C09K11/776; C23C 14/081; C23C sium barium tungstate luminescent thin film exhibits high 14/35; C23C 14/082: C23C 14/3407; C23C luminescence efficiency and highlight emitting peaks in red 14/3414; C23C 14/351; C23C 14/165; C23C and blue regions. Said method presents the advantages of 14/228; C23C 14/5806; H01J 29/385; H01J simplified operation, less cost, and Suitable for industrial 2235/081; H01J 37/3405; H01J 37/3408; preparation. H01J 37/3414; H01J 37/3426; H01J 37/3429; H01J 37/3491; H01S 5/3018; CO3C 17/36 10 Claims, 2 Drawing Sheets

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(51) Int. Cl. JP 58-021477 A 2, 1983 HOI. 37/34 (2006.01) JP O1-263.188 A 10, 1989 HOIS 5/30 (2006.01) E. g A '32. C23C I4/08 (2006.01) JP 08-092553. A 4f1996 C23C I4/35 (2006.01) JP 2003-138257 A 5, 2003 H05B33/14 (2006.01) JP 2003.138257 5, 2003 JP 2005.220299. A 8, 2005 (56) References Cited JP 2006004658 A 1, 2006 JP 2006-2326O1 9, 2006 U.S. PATENT DOCUMENTS WO 2006,111568 A2 10, 2006 2003/0052000 A1* 3/2003 Segal et al...... 204/298.13 2005/0214573 A1 9, 2005 Den et al. 2010, 0151179 A1* 6, 2010 Nishihara ...... C23C 14/08 OTHER PUBLICATIONS 428,64.5 2010/0244.066 A1 9/2010 Chiu et al. Office Action dated Jul. 28, 2014, issued in Chinese Application No. 2011/0168994 A1* 7, 2011 Kawashima et al...... 257/43 2011.8007O930.9 FOREIGN PATENT DOCUMENTS CN 102791052 A * 11, 2012 * cited by examiner U.S. Patent Feb. 23, 2016 Sheet 1 of 2 US 9.270,084 B2

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Figure 5 US 9,270,084 B2 1. 2 CERUM DOPED MAGNESUM BARUM barium oxide is 0.1% to 40%, the content in mass percentage TUNGSTATE LUMINESCENT THIN FILM, of said cerium oxide is 0.01% to 0.8%, the rest is tungsten MANUFACTURING METHOD AND trioxide; APPLICATION THEREOF forming the precursor of cerium doped magnesium barium tungstate luminescent thin film by Subjecting the Sputtering CROSS REFERENCE TO RELATED target to magnetron Sputtering: APPLICATIONS annealing the precursor of cerium doped magnesium barium tungstate luminescent thin film to form the cerium The present application is the U.S. National Phase of Inter doped magnesium barium tungstate luminescent thin film. national patent application Ser. No. PCTICN2011/076467, 10 The embodiment of the present invention further provides filed Jun. 28, 2011, the contents of which are hereby incoi the use of the above-mentioned cerium doped magnesium porated by reference in its entirety. barium tungstate luminescent thin film in electroluminescent devices. TECHNICAL FIELD 15 The Beneficial Effects The present invention relates to the technical field of semi conductor optoelectronic materials, in particular to a cerium The combined use of cerium and magnesium barium tung doped magnesium barium tungstate luminescent thin film, state in the cerium doped magnesium barium tungstate lumi and manufacturing method and application thereof. nescent thin film of the embodiment of the present invention results in a film that exhibits higher luminescence efficiency, BACKGROUND ART and exhibits relatively high. emission peaks in both the red and blue regions, for example emission peaks at 470 nm and Scheelite structured AWO (A=Ca,Sr., Ba) is one important 670 nm, said method of manufacturing the cerium doped type of laser materials. It presents as a tetragonal structure at magnesium barium tungstate luminescent thin film of the room temperature and emits blue light under ultraviolet ray 25 embodiment of the present invention presents the advantages excitation. Barium tungstate maintains its tetragonal struc of simplified operation, low cost, and suitable for industrial ture from room temperature to its melting point (1820 K), and preparation. possesses good structural stability. Due to these excellent properties, barium tungState has an attractive applicable pros BRIEF DESCRIPTION OF THE DRAWING pect in the field of light emitting and display technology, laser 30 and optoelectronics technology and detection technology. At FIG. 1 shows the flowchart of the manufacturing method of present, barium tungstate has been applied to phosphors, but the cerium doped magnesium barium tungstate luminescent less involved in the field of cerium-doped magnesium barium thin film of the embodiment according to the present inven tungstate luminescent thin film, and the resulting film exhibits tion. low luminescence efficiency; further, complicated prepara 35 FIG. 2 shows the XRD patterns of the cerium doped mag tion process is often involved. nesium barium tungstate luminescent thin film obtained from Example 1 according to the present invention. DISCLOSURE OF THE INVENTION FIG. 3 shows the EL spectra of the cerium doped magne sium barium tungstate luminescent thin film obtained from Technical Problems 40 Example according to the present invention. FIG. 4 shows the plot that illustrates the correlation of the In view of this, the embodiment of the present invention luminescent intensity and the position of the emission peaks provides a cerium-doped magnesium barium tungstate lumi of the cerium doped magnesium barium tungstate lumines nescent thin film, and manufacturing method and application cent thin film with the content of magnesium oxide. thereof to solve the technical problems in the prior art, like 45 FIG. 5 shows schematically the structure of an electrolu complicated process for manufacturing a cerium-doped mag minescent device which employs the cerium doped magne nesium barium tungstate luminescent thin film, high cost, low sium barium tungstate luminescent thin film of the embodi luminescence efficiency of a cerium-doped magnesium ment according to the present invention. barium tungstate luminescent thin film. 50 DETAILED DESCRIPTION OF THE Technical Solution EMBODIMENTS The embodiment of the present invention is achieved in the The above and other objects, features, and advantages of following way: the present invention will become more apparent from the providing a cerium-doped magnesium barium tungstate 55 following detailed description when taken in conjunction luminescent thin film, with the accompanying drawings and embodiments. It should having the molecular formula of Mg, Ba, WOs:YCe" be understood that the specific embodiments described herein where x is from range of 0.13 to 0.96, Y is from range of are merely for illustrative purpose. rather than limiting the 0.0002 to 0.0124; present invention. and 60 The embodiment of the present invention provides a providing a method for manufacturing a cerium-doped cerium doped magnesium barium. tungstate luminescent thin magnesium barium tungState luminescent thin film, compris film. ing the following steps: having the molecular formula of Mg, BaWOs:YCe", mixing magnesium oxide, barium oxide, tungsten oxide where x is from range of 0.13 to 0.96, preferably 0.43, Y is and cerium oxide; sintering for forming sputtering target, 65 from range of 0.0002 to 0.0124, preferably 0.0023. wherein the content in mass percentage of said magnesium The cerium doped magnesium barium tungstate lumines oxide is 0.1% to 15%, the content in mass percentage of said cent thin film of the present invention takes magnesium US 9,270,084 B2 3 4 barium tungstate as the luminous host material of the lumi Specifically, in step S02, the ITO substrate and the sputter nescent thin film, and takes elemental cerium as the lumines ing target are loaded into the chamber of a coating device, cence center, which results in relatively high luminescence which the chamber is evacuated by means of a mechanical efficiency in the cerium doped magnesium barium tungstate pump or a molecular pump such that a vacuum level of 1.0x luminescent thin film of the embodiment according to the 10 Pa to 1.0x10 Pa, preferably 5.0x10 Pa, is reached; present invention by making use of the combined use of sputtering is conducted under the following conditions: a magnesium barium tungstate and cerium; and renders the distance of 50 to 100 mm from the substrate to the target, a ability of adjusting the luminescent intensity of the cerium substrate temperature of 250° C. to 750° C., employing a doped magnesium barium tungstate luminescent thin film by mixed gas of hydrogen and an inert gas as the operating gas, varying the content of magnesium and barium in the magne 10 a gas flow rate of 15 to 30 sccm, a pressure of 0.2 to 4.5 Pa, to sium barium tungstate that acts as the luminous host material. give a precursor of cerium doped magnesium barium tung With reference to FIG. 3, FIG. 3 shows the EL spectra of state luminescent thin film. the cerium doped magnesium barium tungstate luminescent In step S02, limitations are not made there to said inert gas, thin film obtained from Example according to the present for example, nitrogen, helium, argon, neon may be used; in invention. As shown in FIG. 1, the cerium doped magnesium 15 said mixed gas of hydrogen and an inert gas, the content in barium tungstate luminescent thin film of the embodiment of Volume percentage of hydrogen in said mixed gas is 1 to 15%, the present invention shows emission peaks at 470 nm and preferably, 10%; wherein, the distance between the substrate 670 nm. With reference to FIG. 4, FIG. 4 shows the plot that and the target is 70 mm, said Substrate temperature is prefer illustrates changes of the luminescent intensity and the posi ably 600° C., said gas flow rate is preferably 25 sccm, said tion of the emission peaks of the cerium doped magnesium pressure is preferably 2.0 Pa. barium tungstate luminescent thin film of the embodiment of Specifically, in step S03, the precursor of cerium doped the present invention by varying the content of magnesium magnesium barium tungState luminescent thin film is Sub oxide. Curve 1 shows changes of the luminescent intensity of jected to annealing in a vacuum furnace at a pressure of 0.01 film curve 2 shows changes of the position of the emission Pa for 1 to 3 h, preferably 2 h, where the annealing tempera peaks of film. As shown in use 4, the luminescent intensity of 25 ture is 500° C. to 800° C., preferably 700° C., to give a cerium the cerium-doped barium magnesium tungstate luminescent doped magnesium barium tungstate luminescent thin film. film firstly increases and then decreases as the content of The method of manufacturing the cerium doped magne magnesium oxide increases. As the content in mass percent sium barium tungstate luminescent thin film of the embodi age of the magnesium oxide in the manufacturing method is ment of the present invention by mixing magnesium oxide, about 6%, the relative luminescent intensity shows the stron 30 barium oxide, tungsten oxide and cerium oxide, sintering for gest with the increase of the content of magnesium oxide, the forming sputtering target, followed by Sputtering for forming wavelength of the emission peaks of the cerium-doped mag film provides the cerium doped magnesium barium tungstate nesium barium tungstate luminescent film becomes shorter. luminescent thin film. Said cerium doped magnesium barium See FIG. 1, a flowchart of the manufacturing method of the tungstate luminescent thin film exhibits relative high lumi cerium doped magnesium barium tungstate luminescent thin 35 nescence efficiency; said method of manufacturing the film of the embodiment according to the present invention is cerium doped magnesium barium tungstate luminescent thin shown, said method comprises the steps of: film of the embodiment of the present invention presents the step S01, manufacturing of the Sputtering target advantages of simplified operation, less cost, and Suitable for mixing magnesium oxide, barium oxide, tungsten oxide industrial preparation. and cerium oxide; sintering for forming sputtering target, 40 The embodiment Of the present invention further provides wherein the content in mass percentage of said magnesium the Use of said cerium doped magnesium barium tungstate oxide is 0.1% to 15%, the content in mass percentage of said luminescent thin film in electroluminescent devices. With barium oxide is 0.1% to 40%, the content in mass percentage reference to FIG. 5, FIG. 5 shows schematically the structure of said cerium oxide is 0.01% to 0.8%, the rest is tungsten of an electroluminescent device which employs the cerium trioxide; 45 doped magnesium barium tungstate luminescent thin film of step S02, magnetron sputtering the embodiment according to the present invention, which forming the precursor of cerium doped magnesium barium comprises anode 1, emission layer 2 and cathode 3. The tungstate luminescent thin film by Subjecting the Sputtering material for said anode 1 is ITO coated glass, the material for target to magnetron Sputtering: said emission layer 2 is the cerium doped magnesium barium step S03, annealing 50 tungstate luminescent thin film of the embodiment according annealing the precursor of cerium doped magnesium to the present invention and the material for said cathode 3 is barium tungstate luminescent thin film to form the cerium silver. doped magnesium barium tungstate luminescent thin film. Detailed description to said cerium doped magnesium Specifically, in step S01, magnesium oxide (MgO), barium barium tungstate luminescent thin film will now be given with oxide (BaO), tungsten oxide (WO) and cerium oxide (CeO) 55 reference to the exemplary embodiments: are powers having a purity of 99.99% or above. The content of magnesium oxide in mass percentage is 0.1% to 15%, pref EXAMPLE 1. erably 2% to 10%, for example, 6%; the content of barium oxide in mass percentage is 0.1% to 40%, preferably 0.2% to Magnesium oxide, barium oxide, tungsten oxide and 30%, for example, 30% the content of cerium oxide in mass 60 cerium oxide are mixed homogenously wherein the contentin percentage is 0.01% to 0.8%, preferably 0.02% to 0.6%, for mass percentage of MgO is 6%, the content in mass percent example, 0.15%. age of BaO is 30%, the content in mass percentage of Ce2O. In step S01, magnesium oxide, barium oxide, tungsten is 0.15%, the rest is WO (in mass percentage); oxide and cerium oxide are mixed homogenously and then The mixture is sintered at a temperature of 1250° C. to form sintered at a temperature of 900° C. to 1300° C. to form a 65 a ceramic sputtering target of db50x2 mm: sputtering target of db50x2min; preferably, said sintering The target is loaded into a vacuum chamber, and the ITO temperature is 1250° C. coated glass Substrate is then Subjected to ultrasonic washing US 9,270,084 B2 5 6 with a sequential use of acetone, anhydrous ethanol and Onto the cerium doped magnesium barium tungstate lumi deionized water, which is then Subjected to oxygen plasma nescent thin film is then deposited a layer of Ag as a cathode, treatment, followed by placing it into the vacuum chamber. to give an electroluminescent device comprising the cerium The distance between the target and the substrate is set to 75 doped magnesium barium tungstate luminescent thin film of mm. The chamber is evacuated by means of a mechanical the embodiment of the present invention. pump and molecular pump such that a vacuum. level 5.0x10' Pa is reached, to which the vacuum chamber is purged with a EXAMPLE 3 mixed gas of argon and hydrogen as the operating gas, where the hydrogen content is 10% (in Volume percentage), the gas Magnesium oxide, barium oxide, tungsten oxide and flow rate is 25 sccm, the pressure is adjusted to 2.0 Pa, the 10 cerium oxide are mixed homogenously, wherein the content substrate temperature is 600°C., a precursor of cerium doped in mass percentage of MgO is 15%, the content in mass magnesium barium tungstate luminescent thin film is formed percentage of BaO is 0.1%, the content in mass percentage of by Sputtering; CeO, is 0.8%, the rest is WO (in mass percentage); the precursor of cerium doped magnesium barium tung 15 The mixture is sintered at a temperature of 1300° C. to form state luminescent thin film is Subjected to annealing in a a ceramic sputtering target of db50x2 min; vacuum furnace at 0.01 Paunder a temperature of 700° C. for The target is loaded into a vacuum chamber, and the ITO 2 h to form the cerium doped magnesium barium tungstate coated glass Substrate is then Subjected to ultrasonic washing luminescent thin film. with a sequential use of acetone, anhydrous ethanol and The thus obtained cerium doped magnesium barium tung deionized water, which is then Subjected to oxygen plasma state luminescent thin film has a molecular formula of treatment, followed by placing it into the vacuum chamber. Mgos Baos, W.O.s:0.0023 Ce"; The distance between the target and the substrate is set to 100 Onto the cerium doped magnesium barium tungstate lumi mm. The chamber is evacuated by means of a mechanical nescent thin turn is then deposited a layer of Ag as a cathode, pump and molecular pump such that a vacuum level 10x10 to give an electroluminescent device comprising the cerium 25 Pa is reached, to which the vacuum chamber is purged with a doped magnesium barium tungstate luminescent thin film of mixed gas of argon and hydrogen as the operating gas, where the embodiment of the present invention. the hydrogen content is 15% (in Volume percentage), the gas With reference to FIG. 2, FIG.2 shows the XRD patterns of flow rate is 30 sccm, the pressure is adjusted to 4.5 Pa, the the cerium doped magnesium barium tungstate luminescent substrate temperature is 600° C. a precursor of cerium doped thin film obtained from Example 1 according to the present 30 magnesium barium tungstate luminescent thin film is formed invention, which, as compared with standard PDF card cor by Sputtering; responds to the crystallization peaks of barium tungstate, the precursor of cerium doped magnesium barium tung whereas diffraction peaks are not found for the doping ele state luminescent thin film is Subjected to annealing in a ments and other impurities. 35 vacuum furnace at 0.01 Paunder a temperature of 800° C. for EXAMPLE 2 3 h to form the cerium doped magnesium barium tungstate luminescent thin film. Magnesium oxide, barium oxide, tungsten oxide and The thus obtained cerium doped magnesium barium tung cerium oxide are mixed homogenously, wherein the content state luminescent thin film has a molecular formula of in mass percentage of MgO is 0.1%, the content in mass 40 Mgolo Baoo, WOs: 0.0124 Ce"; percentage of BaO is 40%, the content in mass percentage of Onto the cerium doped magnesium barium tungstate lumi CeO, is 0.01%, the rest is WO (in mass percentage); nescent thin film is then deposited a layer of Ag as a cathode, The mixture is sintered at a temperature of 900° C. to form to give an electroluminescent device comprising the cerium a ceramic sputtering target of db50x2 mm: doped magnesium barium tungstate luminescent thin film of The target is loaded into a vacuum chamber, and the ITO 45 the embodiment of the present invention. coated glass Substrate is then subjected to ultrasonic washing with a sequential use of acetone, anhydrous ethanol and EXAMPLE 4 deionized water, which is then Subjected to oxygen plasma treatment, followed by placing it into the vacuum chamber. Magnesium oxide, barium oxide, tungsten oxide and The distance between the target and the substrate is set to 50 50 cerium oxide are mixed homogenously, wherein the content mm. The chamber is evacuated by means of a mechanical in mass percentage of MgO is 0.2%, the content in mass pump and molecular pump such that a vacuum level 1.0x10 percentage of BaO is 30%, the content in mass percentage of Pa is reached, to which the vacuum chamber is purged with a CeO is 0.6%, the rest is WO (in mass percentage); mixed gas of argon and hydrogen as the operating gas, where The mixture is sintered at a temperature of 900° C. to form the hydrogen content is 1% (in Volume percentage), the gas 55 a ceramic sputtering target of db50x2 mm: flow rate is 15 sccm, the pressure is adjusted to 0.2 Pa, the The target is loaded into a vacuum chamber, and the ITO substrate temperature is 600°C., a precursor of cerium doped coated glass Substrate is then Subjected to ultrasonic washing magnesium barium tungstate luminescent thin film is formed with a sequential use of acetone, anhydrous ethanol and by Sputtering: deionized water, which is then Subjected to oxygen plasma the precursor of cerium doped magnesium barium tung 60 treatment, followed by placing it into the vacuum chamber. state luminescent thin film is Subjected to annealing in a The distance between the target and the substrate is set to 50 vacuum furnace at 0.01 Paunder a temperature of 500° C. for mm. The chamber is evacuated by means of a mechanical 1 h to form the cerium doped magnesium barium tungstate pump and molecular pump such that a vacuum. level 5.0x luminescent thin film. 10 Pa is reached, to which the vacuum chamber is purged The thus obtained cerium doped magnesium barium tung 65 with a mixed gas of argon and hydrogen as the operating gas, state luminescent thin film has a molecular formula of where the hydrogen content is 8% (in Volume percentage), the Mgolois Baos, WOs:0.0002 Ce"; gas flow rate is 20 sccm, the pressure is adjusted to 0.2 Pa, the US 9,270,084 B2 7 8 substrate temperature is 600°C., a precursor of cerium doped mm. The chamber is evacuated by means of a mechanical magnesium barium tungstate luminescent thin film is formed pump and molecular pump such that a vacuum. level 5.0x by Sputtering; 10 Pa is reached, to which the vacuum chamber is purged the precursor of cerium doped magnesium barium tung with a mixed gas of argon and hydrogen as the operating gas, 5 where the hydrogen content is 9% (in Volume percentage), the state luminescent thin film is Subjected to annealing in a gas flow rate is 20 sccm, the pressure is adjusted to 2.0 Pa the vacuum furnace at 0.01 Paunder a temperature of 500° C. for substrate temperature is 600°C., a precursor of cerium doped 2 h to form the cerium doped magnesium barium tungstate magnesium barium tungstate luminescent thin film is formed luminescent thin film. by Sputtering; The thus obtained cerium doped magnesium barium tung the precursor of cerium doped magnesium barium tung state luminescent thin film has a molecular formula of 10 state luminescent thin film is Subjected to annealing in a Mgolo Baoo, W.O.s:0.0093Ce"; vacuum furnace at 0.01 Paunder a temperature of 750° C. for Onto the cerium doped magnesium barium tungstate lumi 2.5 h to form the cerium doped magnesium barium tungstate nescent thin film is then deposited a layer of Ag as a cathode, luminescent thin flint to give an electroluminescent device comprising the cerium The thus obtained cerium doped magnesium barium tung doped magnesium barium tungstate luminescent thin film of 15 state luminescent thin film has a molecular formula of the embodiment of the present invention. Mgoza Bao.2WOs:0.0124Ce"; Onto the cerium doped magnesium barium tungstate lumi EXAMPLE 5 nescent thin film is then deposited a layer of Ag as a cathode, Magnesium oxide barium oxide, tungsten oxide and to give an electroluminescent device comprising the cerium cerium oxide are mixed homogenously wherein the contentin doped magnesium barium tungstate luminescent thin film of mass percentage of MgO is 10%, the content in miss percent the embodiment of the present invention. age of BaO is 0.2% the content in mass percentage of CeO. Although the present invention has been described and is 0.4% the rest is WO (in mass percentage); illustrated in detail, it is clearly understood that the same is by The mixture is sintered at a temperature of 1300° C. to form way of illustrating the preferred embodiment of the present a ceramic sputtering target of db50x2min; 25 invention and is not to be taken by way of limitation, it should The target is loaded into a vacuum chamber, and the ITO be understood that various changes, Substitutions, and alter coated glass Substrate is then subjected to ultrasonic washing ations could be made hereto without departing from the spirit with a sequential use of acetone, anhydrous ethanol and and scope of the invention. deionized water, which is then Subjected to oxygen plasma What is claimed is: treatment, followed by placing it into the vacuum chamber. 30 1. A cerium doped magnesium barium tungstate lumines The distance between the target and the substrate is set to 80 cent thin film, wherein said cerium doped magnesium barium mm. The chamber is evacuated by means of a mechanical tungstate luminescent thin film has the molecular formula of pump and molecular pump such that a vacuum. level 5.0x Mg, Ba, W.Os:yCe", wherex is from range of 0.13 to 0.96, 10 Pa is reached, to which the vacuum chamber is purged y is from range of 0.0002 to 0.0124. with a mixed gas of argon and hydrogen as the operating gas, 35 2. The cerium doped magnesium barium tungstate lumi where the hydrogen content is 11% (in Volume percentage), nescent thin film according to claim 1, wherein X is 0.43, y is the gas flow rate is 23 sccm, the pressure is adjusted to 2.0 Pa., O.OO23. the substrate temperature is 600° C., a precursor of cerium 3. A method of manufacturing a cerium doped magnesium doped magnesium barium tungstate luminescent thin film is barium tungstate luminescent thin film wherein said method formed by sputtering; comprises the steps of the precursor of cerium doped magnesium barium tung 40 mixing magnesium oxide, barium oxide, tungsten trioxide state luminescent thin film is Subjected to annealing in a and cerium oxide to obtain a mixture; vacuum furnace at 0.01 Paunder a temperature of 650° C. for forming the mixture into a target body; 2 h to form the cerium doped magnesium barium tungstate sintering the target body for forming sputtering target, luminescent thin film. wherein the content in mass percentage of said magne The thus obtained cerium doped magnesium barium tung 45 sium oxide is 0.1% to 15%, the content in mass percent state luminescent thin film has a molecular formula of age of said barium oxide is 0.1% to 40%, the content in MgolossBacoos WOs:0.0062Ce"; mass percentage of said cerium oxide is 0.01% to 0.8%, Onto the cerium doped magnesium barium tungstate lumi the rest is tungsten trioxide; nescent thin film is then deposited a layer of Ag as a cathode, providing a Substrate upon which a cerium doped magne to give an electroluminescent device comprising the cerium 50 sium barium tungstate luminescent thin film is formed; doped magnesium barium tungstate luminescent thin film of forming the precursor of cerium doped magnesium barium the embodiment of the present invention. tungstate luminescent thin film by magnetron Sputter ing; and EXAMPLE 6 annealing the precursor of cerium doped magnesium barium tungstate luminescent thin film to obtain the Magnesium oxide, barium oxide, tungsten oxide and 55 cerium doped magnesium barium tungstate luminescent cerium oxide are mixed homogenously wherein the contentin thin film. mass percentage of MgO is 15%, the content in mass percent 4. The method of manufacturing a cerium doped magne age of BaO is 20%, the content in mass percentage of CeO sium barium tungstate luminescent thin film according to is 0.8%, the rest is WO (in mass percentage) claim 3, wherein the content in mass percentage of said mag The mixture is sintered at a temperature of 1000°C. to form 60 nesium oxide is 0.2% to 10%, the content in mass percentage a ceramic sputtering target of db50x2 mm: of said barium oxide is 0.2% to 30%, the content in mass The target is loaded into a vacuum chamber, and the ITO percentage of said cerium oxide is 0.02% to 0.6%, the rest is coated glass Substrate is then subjected to ultrasonic washing tungsten trioxide. with a sequential use of acetone, anhydrous ethanol and 5. The method of manufacturing a cerium doped magne deionized water, which is then Subjected to oxygen plasma 65 sium barium tungstate luminescent thin film according to treatment, followed by placing it into the vacuum chamber. claim 3, wherein the content in mass percentage of said mag The distance between the target and the substrate is set to 95 nesium oxide is 6%, the content in mass percentage of said US 9,270,084 B2 10 barium oxide is 30%, the content in mass percentage of said cerium oxide is 0.15%, the rest is tungsten trioxide. 6. The method of manufacturing a cerium doped magne sium barium tungstate luminescent thin film according to claim 3, wherein said sintering is conducted at a temperature of 900° C. to 1300° C. 7. The method of manufacturing a cerium doped magne sium barium tungstate luminescent thin film according to claim 3, wherein said sputtering is conducted under the fol lowing conditions: the distance between the substrate and the 10 target is 50 to 100 mm, the substrate temperature is 250° C. to 750° C. employing a mixed gas of hydrogen and an inert gas as the operating gas, gas flow rate is 15 to 30s.ccm, pressure is O2 to 4.5Pa. 8. The method of manufacturing a cerium doped magne 15 sium barium tungstate luminescent thin film according to claim 7, wherein the content in Volume percentage of hydro gen in said mixed gas is 1% to 15%. 9. The method of manufacturing a cerium doped magne sium barium tungstate luminescent thin film according to claim3, wherein said annealing is conducted at a temperature of 500° C. to 800° C. for a time period of 1 to 3 h. 10. An electroluminescent device, comprising a cerium doped magnesium barium tungstate luminescent thin film according to claim 1. 25