JP2005076024A - Method for preparing thin film of rare earth element-doped gallium oxide-tin oxide multicomponent oxide fluorescent material for electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin film of gallium oxide-tin oxide multicomponent oxide fluorescent material, emitting high luminance light by controlling composition of a matrix material and thermal treatment condition in the amorphous multicomponent oxide matrix material comprising gallium oxide and tin oxide as main components doped with at least a kind of rare earth elements as a luminous center substance, and to provide a method for producing the same. <P>SOLUTION: The invention is performed in the following processes, a process for controlling the atomic ratio of tin to gallium from 5 to 95 atomic.%, preferably 14 to 18 atomic.% and a process for controlling the fluorescent thin film to contain Ga<SB>4</SB>SnO<SB>8</SB>as a principal component which is a ternary compound in the gallium oxide-tin oxide multiple oxide doped with Eu, and a process for thermally treating in an oxidative atmosphere at comparatively low temperature of 400-800°C, preferably 500-700°C thereby forming the amorphous thin film. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

Detailed Description of the Invention

Industrial application fields

The present invention relates to a method for producing a rare earth-added gallium oxide-tin oxide multielement phosphor thin film for an electroluminescence element.

Reported by the applicants (T. Minami, T. Miyata, T. Shirai and T. Nakatani, Mat. Res Soc. Symp. Proc. Vol 621 (2000) p. Q4.3.1) Rare earth elements as luminescent center materials In order to obtain EL emission, the gallium oxide-tin oxide phosphor thin film to which europium (Eu) is added has been subjected to heat treatment at a high temperature of about 1000 ° C. to produce a polycrystalline thin film.

Problems to be solved by the invention

However, light emission from a thin film electroluminescent device (hereinafter referred to as EL device) using the Eu-doped gallium oxide-tin oxide oxide phosphor thin film as a light emitting layer is weak, and it is practical as a light emitting layer material for thin film EL lamps and thin film EL displays. The brightness that can withstand In addition, since the heat treatment temperature is as high as about 1000 ° C., there is a problem that a low-melting point base material such as glass conventionally used in thin film EL elements cannot be used.

Means for solving the problem

In the present invention, the atomic ratio of tin to gallium in the Eu-doped gallium oxide-tin oxide multi-component oxide phosphor thin film is 5 to 95 atomic%, preferably 14 to 18 atomic%, and the phosphor thin film is a ternary compound. The film composition is controlled so that Ga ₄ SnO ₈ as a main component is formed, and then heat treatment is performed at a relatively low temperature of 400 to 800 ° C., preferably 500 to 700 ° C. in an oxidizing atmosphere. Thus, the above problem can be solved by using a manufacturing method for forming an amorphous thin film.

In the present invention, the Eu-doped gallium oxide-tin oxide multisystem oxide phosphor thin film is sputtered in an inert gas atmosphere, chemical vapor deposition (CVD), electron beam deposition, activated reactive deposition. (ARE) method, cluster ion beam (ICB) method, ion beam sputtering (IBS) method, atomic layer epitaxial (ALE) growth method, molecular beam epitaxial growth (MBE) method, gas source MBE (or CBE) method, electron cyclotron resonance (ECR) A relatively low temperature of about 400 to 800 ° C., preferably about 500 to 700 ° C., in an atmosphere containing an oxidizing gas such as the atmosphere, which is manufactured using a known thin film deposition technique such as a crystal growth method using plasma. It is possible to provide sufficient functions as a light emitting layer for EL elements by performing a heat treatment in order to form an amorphous film. It is characterized to be able to realize a luminance sufficiently withstand practical use. Further, taking advantage of the chemical stability of the Eu-doped gallium oxide-tin oxide multi-component oxide phosphor thin film, a conventional wet chemical film formation method such as a solution coating method or a sol-gel method is used. The law is also effective.

A thin film prepared by making full use of a manufacturing method in which the Eu-doped gallium oxide-tin oxide multi-component oxide phosphor thin film according to the present invention is heat-treated at a relatively low temperature of about 400 to 800 ° C., preferably about 500 to 700 ° C. High luminance red light emission was realized in the EL element.

Action

The gallium oxide-tin oxide phosphor thin film to which europium (Eu), which is a rare earth element, is added as the luminescent center material is heat-treated at a high temperature of about 1000 ° C. to obtain EL luminescence. Was. Further, it has been considered that the composition ratio of the base material of the gallium oxide-tin oxide oxide phosphor thin film needs to be suitable for obtaining a polycrystal. However, as a result of various studies on the manufacturing method and production conditions of the gallium oxide-tin oxide multi-component oxide phosphor thin film, the applicants conducted heat treatment at a lower temperature and in an appropriate oxidizing atmosphere. The present inventors have invented a new method for producing the gallium oxide-tin oxide multi-component oxide phosphor thin film having the effect of realizing high-luminance red light emission by producing the amorphous phosphor thin film. In addition, since the phosphor manufacturing method may be a heat treatment process at a relatively low temperature of about 400 to 700 ° C. in an atmosphere containing an oxidizing gas such as the atmosphere, it has been conventionally used in EL devices as a base material. It is possible to use a low-melting-point material such as glass, which is extremely advantageous for increasing the area and definition of the EL element. In addition, the effect of changing the emission spectrum can be expected by the interaction between the co-added element and the emission center.

Hereinafter, the present invention will be described with reference to examples.
(Example 1)

Sufficient to contain 6.0 atomic% of europium dioxide (Eu ₂ O ₃ ) powder as a luminescent center material with respect to Ga in a powder in which 16.5 atomic% of tin (Sn) is mixed with gallium (Ga) After mixing, the powder was baked at 1000 ° C. for 1 hour in an argon (Ar) gas atmosphere to produce Eu-doped gallium oxide-tin oxide multi-component oxide phosphor powder. A sputtering target was prepared using the phosphor powder, and on the sintered barium titanate (BaTiO ₃ ) ceramic substrate / insulator layer, in argon (Ar) gas, gas pressure 6 Pa, sputtering input power 100 W, substrate temperature 275 An Eu-added gallium oxide-tin oxide multi-component oxide phosphor light-emitting layer was formed under the conditions of ° C and a substrate-target distance of 25 mm. Then, annealing treatment was performed at 500 to 900 ° C. for 1 hour in the air.

FIG. 1 shows the annealing temperature dependence of the photoluminescence (PL) spectrum of the phosphor thin film. As shown in the figure, the PL emission intensity had a peak at a relatively low temperature of about 600 ° C. and decreased at a temperature higher than that. Further, the phosphor thin film subjected to heat treatment at 600 ° C. was amorphous as a result of X-ray diffraction measurement. Further, as shown in FIG. 2, the luminescent color was able to realize red luminescence with a color purity that can be sufficiently put into practical use. Moreover, when the phosphor thin film was excited with an electron beam, a high emission efficiency red cathode luminescence (CL) equivalent to or higher than that of a commercially available red phosphor could be realized.

An EL element was prepared by forming an aluminum-added zinc oxide (ZnO: Al) transparent electrode on the light emitting layer thin film and a metal Al electrode on the back surface. When a 1 kHz sine wave AC voltage was applied to the EL element, the highest luminance was achieved in the EL element using the phosphor thin film that was heat-treated at 600 ° C. as shown in FIG. 3, and the maximum luminance was 162 cd / m. ^Thus, high luminance red EL light emission that can sufficiently withstand the practical use of No. ² was realized. As a result, the Eu-doped gallium oxide-tin oxide multi-component oxide phosphor thin film light emitting layer sufficiently functioned as a light emitting layer thin film for an EL element.
(Example 2)

Europium dioxide (Eu ₂ O ₃ ) powder as a luminescent center material was sufficiently mixed so as to contain 6.0 atomic% with respect to Ga in a powder in which 33 atomic% of tin (Sn) was mixed with gallium (Ga). Thereafter, the resultant was baked at 1000 ° C. for 1 hour in an argon (Ar) gas atmosphere to produce Eu-doped gallium oxide-tin oxide multi-component oxide phosphor powder. A sputtering target was prepared using the phosphor powder, and on the sintered barium titanate (BaTiO ₃ ) ceramic substrate / insulator layer, in argon (Ar) gas, gas pressure 6 Pa, sputtering input power 100 W, substrate temperature 275 An Eu-added gallium oxide-tin oxide multi-component oxide phosphor light-emitting layer was formed under the conditions of ° C and a substrate-target distance of 25 mm. Thereafter, annealing treatment was performed at 600 ° C. for 1 hour in the air.

The phosphor thin film heat-treated at 600 ° C. was amorphous as a result of X-ray diffraction measurement. In addition, the PL emission color was able to realize red emission with a color purity that could be sufficiently put into practical use. Moreover, when the phosphor thin film was excited with an electron beam, a high emission efficiency red cathode luminescence (CL) equivalent to or higher than that of a commercially available red phosphor could be realized.

An EL element was prepared by forming an aluminum-added zinc oxide (ZnO: Al) transparent electrode on the light emitting layer thin film and a metal Al electrode on the back surface. When a 1 kHz sine wave AC voltage was applied to the EL element, red EL light emission with a luminance sufficient for practical use could be realized.
(Example 3)

Sufficient to contain 6.0 atomic% of europium dioxide (Eu ₂ O ₃ ) powder as a luminescent center material with respect to Ga in a powder in which 16.5 atomic% of tin (Sn) is mixed with gallium (Ga) After mixing, the powder was baked at 1000 ° C. for 1 hour in an argon (Ar) gas atmosphere to produce Eu-doped gallium oxide-tin oxide multi-component oxide phosphor powder. A sputtering target is prepared using the phosphor powder, and a sintered barium titanate (BaTiO ₃ ) ceramic substrate / insulator layer is placed on an argon (Ar) gas with a gas pressure of 6 Pa, a sputtering input power of 100 W, and a substrate temperature of 350. An Eu-added gallium oxide-tin oxide multi-component oxide phosphor light-emitting layer was formed under the conditions of ° C and a substrate-target distance of 25 mm. Thereafter, annealing treatment was performed at 600 ° C. for 1 hour in the air.

As a result of X-ray diffraction measurement, the phosphor thin film subjected to heat treatment at 600 ° C. was amorphous including Ga ₄ SnO ₈ . In addition, the PL emission color was able to realize red emission with a color purity that could be sufficiently put into practical use. Moreover, when the phosphor thin film was excited with an electron beam, a high emission efficiency red cathode luminescence (CL) equivalent to or higher than that of a commercially available red phosphor could be realized.

An EL element was prepared by forming an aluminum-added zinc oxide (ZnO: Al) transparent electrode on the light emitting layer thin film and a metal Al electrode on the back surface. When a 1 kHz sine wave AC voltage was applied to the EL element, red EL light emission with a luminance sufficient for practical use could be realized.
Example 4

Europium dioxide (Eu ₂ O ₃ ) powder as a luminescent center material in a powder in which 16.5 atomic% of tin (Sn) is mixed with gallium (Ga) is contained in an amount of 0.5 to 10 atomic% with respect to Ga. Then, the mixture was baked at 1000 ° C. for 1 hour in an argon (Ar) gas atmosphere to produce Eu-doped gallium oxide-tin oxide multi-component oxide phosphor powder. A sputtering target was prepared using the phosphor powder, and on the sintered barium titanate (BaTiO ₃ ) ceramic substrate / insulator layer, in argon (Ar) gas, gas pressure 6 Pa, sputtering input power 100 W, substrate temperature 275 An Eu-added gallium oxide-tin oxide multi-component oxide phosphor light-emitting layer was formed under the conditions of ° C and a substrate-target distance of 25 mm. Thereafter, annealing treatment was performed at 600 ° C. for 1 hour in the air.

FIG. 4 shows the Eu addition amount dependence of the photoluminescence (PL) spectrum of the phosphor thin film. As shown in the figure, the PL intensity had a peak at an Eu addition amount of 6 atomic% and decreased at an addition amount higher than that.

An EL device was fabricated by forming an aluminum soot-added zinc oxide (ZnO: Al) transparent electrode on the light emitting layer thin film and a metal Al electrode on the back surface. When a 1 kHz sine wave AC voltage is applied to the EL element, the EL element using the phosphor thin film produced with an Eu addition amount of 6 atomic% can achieve the highest luminance, and has a color purity that can sufficiently withstand practical use. EL emission was achieved. As a result, the Eu-doped gallium oxide-tin oxide multi-component oxide phosphor thin film light emitting layer sufficiently functioned as a light emitting layer thin film for an EL element.
(Example 5)

5. Europium dioxide (Eu ₂ O ₃ ) and manganese dioxide (MnO ₂ ) powders as a luminescent center material in a powder obtained by mixing 16.5 atomic% of tin (Sn) with respect to gallium (Ga), respectively. After sufficiently mixing to contain 0 atomic% and 2 atomic%, it is fired in an argon (Ar) gas atmosphere at 1000 ° C. for 1 hour, whereby Eu and Mn co-doped gallium oxide-tin oxide multicomponent oxide fluorescence A body powder was prepared. A sputtering target was prepared using the phosphor powder, and on the sintered barium titanate (BaTiO ₃ ) ceramic substrate / insulator layer, in argon (Ar) gas, gas pressure 6 Pa, sputtering input power 100 W, substrate temperature 275 An Eu-added gallium oxide-tin oxide multi-component oxide phosphor light-emitting layer was formed under the conditions of ° C and a substrate-target distance of 25 mm. Thereafter, annealing treatment was performed in the atmosphere at 700 ° C. for 1 hour.

Red and green PL emissions were observed from the phosphor thin film. An EL device was fabricated by forming an aluminum soot-added zinc oxide (ZnO: Al) transparent electrode on the light emitting layer thin film and a metal Al electrode on the back surface. When a 1 kHz sine wave AC voltage was applied to the EL element, in the EL element using the phosphor thin film, the EL emission color changed from green to red as the applied voltage increased. As a result, the Eu and Mn co-doped gallium oxide-tin oxide multi-component oxide phosphor thin film light emitting layer sufficiently functioned as a light emitting layer thin film for EL elements.

The invention's effect

According to the present invention, an Eu-doped gallium oxide-tin oxide multi-component oxide phosphor thin film is formed using a known film formation technique, and the atomic ratio of tin to gallium in the film is 5 to 95 atomic%, preferably 14 To 18 atomic%, and the phosphor thin film is formed by controlling the composition of the film so as to contain Ga ₄ SnO ₈ which is a ternary compound, and thereafter in an oxidizing atmosphere, 400 to 800 ° C., preferably 500 to By using a manufacturing method in which an amorphous thin film is formed by performing a heat treatment at a relatively low temperature of 700 ° C., high photoluminescence (PL), cathodoluminescence (CL), and electroluminescence (EL). Bright red emission was achieved. In particular, as a light emitting layer material for an EL element, high color purity can be realized, and in addition, the phosphor has extremely high chemical stability peculiar to oxides. From the above, the thin film phosphor can be widely applied as a phosphor such as a thin film EL element, a fluorescent lamp, a plasma display, and a cathode ray tube, and its effect is enormous.

Dependence of annealing temperature on photoluminescence (PL) spectrum of the phosphor thin film in Example 1 CIE chromaticity coordinates of photoluminescence (PL) of the phosphor thin film in Example 1 Luminance-applied voltage characteristics at the time of 1 kHz sine wave driving of a thin film EL element using the phosphor thin film as a light emitting layer in Example 1 Dependence of Eu on the photoluminescence (PL) spectrum of the phosphor thin film in Example 4

Claims (10)

In an amorphous phosphor obtained by adding at least one kind of rare earth element as a luminescent center material to a Ga—Sn—O-based oxide base material containing gallium (Ga) and tin (Sn) as main components, A multi-component oxide phosphor for a thin-film electroluminescence device, wherein the composition of the base material is an atomic ratio of tin to gallium of 5 to 95 atomic%. An amorphous phosphor obtained by adding at least one kind of rare earth element as an emission center material to the Ga—Sn—O-based oxide matrix material according to claim 1, wherein the composition of the matrix material is smaller than that of gallium. A multi-element oxide phosphor for a thin-film electroluminescent device, wherein the atomic ratio of tin is 14 to 18 atomic%. 3. An amorphous phosphor obtained by adding at least one kind of rare earth element as a luminescent center material to the Ga—Sn—O-based oxide matrix material according to claim 1 or 2, wherein the matrix material is gallium oxide ( A multi-component oxide phosphor for a thin-film electroluminescence device, which is a composite oxide containing Ga ₂ O ₃ ) and tin oxide (SnO ₂ ). 3. An amorphous phosphor obtained by adding at least one kind of rare earth element as an emission center material to the Ga—Sn—O-based oxide matrix material according to claim 1 or 2, wherein the matrix material is a ternary compound. A multi-component oxide phosphor for a thin-film electroluminescence device, characterized in comprising Ga ₄ SnO ₈ as a main component. The multi-component oxide phosphor for a thin-film electroluminescence device according to claim 1, wherein the emission center material is europium (Eu). 6. The thin film according to claim 1, wherein europium (Eu) added as a luminescent center material is 1 to 11 atomic%, preferably 4 to 8 atomic%, based on gallium (Ga) as a base material. Multi-element oxide phosphor for electroluminescence element. The multi-element oxide phosphor for a thin film electroluminescent device according to claim 1, wherein at least one kind of arbitrary element is co-added in addition to Eu as the luminescent center material. A thin film electroluminescent device using the Ga—Sn—O-based oxide phosphor according to claim 1 as a light emitting layer. A thin film of the Ga-Sn-O-based oxide phosphor according to any one of claims 1 to 7 is formed by an arbitrary manufacturing method, and then heat-treated in an oxidizing atmosphere at 400 to 800 ° C, preferably 500 to 700 ° C. A method for producing a multi-element oxide phosphor thin film for a thin film electroluminescence device. A method for producing a thin film electroluminescent device, wherein the thin film of the gallium oxide-tin oxide multi-component oxide phosphor according to claim 1 produced by the production method according to claim 9 is used as a light emitting layer. .

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