JP2013224244A - Zinc oxide raw material powder used for aerosol deposition method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide zinc oxide powder as a film deposition raw material capable of improving remarkably the deposition rate of a zinc oxide film in an aerosol deposition method.SOLUTION: Zinc oxide powder includes a dopant element and/or a plurality of zinc oxide particles comprising a zinc oxide crystal including oxygen deficiency. The zinc oxide crystal has jointly crystallinity defined by such a property that the half value width of a zinc oxide (101) plane peak in X-ray diffraction is ≤0.11°, and easily distortive property defined by such a property that the half value width of the (101) plane peak is increased to a value of three times or more when grinding by a planetary ball mill using an alumina pot and an alumina ball is applied at the rate of 200 rpm for one hour.

Description

  The present invention relates to a zinc oxide powder used as a film forming raw material in an aerosol deposition method.

  In recent years, an aerosol deposition method (hereinafter also referred to as an AD method) has attracted attention as a method capable of forming a dense ceramic film at room temperature. In this AD method, when aerosolized raw material particles collide with the substrate at high speed, the particles are plastically deformed by the generated stress, and the film is formed by mechanochemical reaction between the activated particle surface and the substrate. It has been. Therefore, raw material particles are described in Non-Patent Document 1 (supervised by Jun Akira, “From Basics to Applications of Aerosol Deposition Method”, CMC Publishing, issued June 30, 2008, pages 45-46). As is apparent, it is known that the easier the plastic deformation, the higher the film-forming property. However, since zinc oxide has an anisotropic particle strength in terms of crystal structure, brittle fracture is likely to occur in the slip surface direction without plastic deformation, and film formability is poor.

  Patent Document 1 (Japanese Patent Laid-Open No. 2009-249720) discloses a zinc oxide film formed by using an indirect grinding AD method. In this document, in addition to the conventional ejection nozzle used for AD film formation, by separately using an ejection nozzle that ejects particles for crushing the ejected particles, the particles are crushed before colliding with the substrate, It has been proposed to form a film on the surface of a soft resin substrate.

  Patent Document 2 (Japanese Patent Laid-Open No. 2009-087898) discloses a method for producing an aluminum-doped zinc oxide transparent conductive film using the AD method. In this document, since the raw material powder used in the AD method is mechanically pulverized, it is understood that the raw material powder particles have low crystallinity.

JP 2009-249720 A JP 2009-087898 A

Supervised by Jun Meido, “From the basics to the application of the aerosol deposition method”, CMC Publishing, published June 30, 2008, pages 45-46

  The inventors of the present invention have noticeably increased the deposition rate of a zinc oxide film by performing an aerosol deposition method using a specific zinc oxide powder that has high crystallinity but also has high strain resistance to stress. The knowledge that it can be improved is obtained.

  Accordingly, an object of the present invention is to provide a zinc oxide powder capable of remarkably improving the deposition rate of the zinc oxide film in the aerosol deposition method.

According to one aspect of the present invention, a zinc oxide powder used as a film forming raw material in an aerosol deposition method,
The zinc oxide powder comprises a plurality of zinc oxide particles composed of zinc oxide crystals containing a dopant element and / or oxygen deficiency,
The zinc oxide crystals are
Crystallinity defined by the half width of the zinc oxide (101) plane peak in X-ray diffraction being 0.11 ° or less;
Easily distorted as defined by the fact that the half-width of the (101) plane peak increases to a value of 3.0 times or more when pulverization by a planetary ball mill using an alumina pot and alumina balls is performed at 200 rpm for 1 hour. A zinc oxide powder having the same structure is provided.

  According to another aspect of the present invention, there is provided a method for producing a zinc oxide coating by an aerosol deposition method using the zinc oxide raw material powder according to the above aspect.

  According to still another aspect of the present invention, there is provided use of the zinc oxide raw material powder according to the above aspect as a film forming raw material in an aerosol deposition method.

It is a figure explaining the half value width of the zinc oxide (101) plane peak in X-ray diffraction. 2 is a schematic diagram illustrating a configuration of a film forming apparatus used in Example 1. FIG. 2 is an SEM image obtained by photographing the sample powder obtained in Example 1. 10 is an SEM image obtained by photographing sample powder from which coarse particles have been removed by airflow classification in Example 8.

Zinc oxide powder The zinc oxide powder according to the present invention is a zinc oxide powder used as a film forming raw material in the AD method. This zinc oxide powder comprises a plurality of or innumerable zinc oxide particles composed of zinc oxide crystals containing dopant elements and / or oxygen vacancies. The zinc oxide crystal has high crystallinity but also has easy strain against stress. This high crystallinity is defined by the fact that the half width of the zinc oxide (101) plane peak in X-ray diffraction is 0.11 ° or less. On the other hand, the easy strain to stress increases the half-value width of the (101) plane peak to a value of 3.0 times or more when pulverization by a planetary ball mill using an alumina pot and alumina balls is performed at 200 rpm for 1 hour. Is defined by

  Thus, the zinc oxide powder of the present invention is characterized by having high crystallinity. This feature is different from conventional technical common sense that it is believed that the lower the crystallinity of the raw material powder is, in AD film formability, the more advantageous. That is, as clearly shown in Non-Patent Document 1, since the conventional zinc oxide powder has a crystal structure that is not easily distorted, it is easily cracked in the direction of the slip surface without plastic deformation. It was difficult. For this reason, it is generally considered that in the AD method, by reducing the crystallinity of the zinc oxide raw material before film formation, cracking at a specific crystal plane is prevented and film formation is improved. I came. In fact, in Patent Document 2 described above, since the raw material powder used in the AD method is mechanically pulverized, it is understood that the crystallinity of the raw material powder particles is low.

  However, according to the present knowledge of the present inventors, when the crystallinity of the raw material powder particles is low before the film formation, plastic deformation becomes difficult, so that the crystallinity is preferably higher. That is, the present inventors have found that the film forming rate is higher as the raw material has higher crystallinity before film formation and whose crystallinity is significantly reduced by stress such as mechanical crushing. Based on this knowledge, when the mechanical pulverization is performed, the powder with the larger change in crystallinity of the particles before and after the film improves the film-forming speed (that is, the particles are plastically deformed and collide with the substrate at the time of collision with the substrate). The present inventors thought that this would be easier. The present invention is characterized in that the crystallinity change of the particles before and after the pulverization is large, that the half width of the zinc oxide (101) plane peak in X-ray diffraction is 0.11 ° or less, and a planetary ball mill under predetermined conditions. It is specified by satisfying both that the half width of the (101) plane peak increases to a value of 3.0 times or more when pulverization is performed. That is, the former half-width means that the crystallinity is high, while the latter half-width increase rate means that the crystal structure tends to be distorted with respect to stress (ie, the crystallinity is likely to decrease). In addition, the amount of change in crystallinity of the particles before and after pulverization increases, and as a result, plastic deformation is likely to occur, and the film formation rate is improved.

  Thus, in the zinc oxide crystal constituting the zinc oxide powder of the present invention, the half width of the zinc oxide (101) plane peak in X-ray diffraction is 0.11 ° or less, preferably 0.08 ° or less. More preferably, it is 0.075 ° or less. Such a small half width means that the crystallinity is high. This half-value width is obtained by, for example, using an X-ray diffractometer (manufactured by Bruker AX) with a tube current of 40 mA, a tube voltage of 40 kV, a light receiving slit of 0.2 mm, a divergence slit of 0.6 °, a scattering slit of 0.6 °, and a solar slit of 4 °. X-ray diffraction can be carried out under the above conditions, and the half width of the obtained zinc oxide (101) peak can be measured. At that time, the half width is 1 / of the maximum value of the peak as shown in FIG. 1 after smoothing, background removal, and Kα2 peak removal for the zinc oxide (101) peak of the XRD profile. It can be determined by obtaining the lateral width when the peak shape is cut at a position where the intensity is 2.

  Further, the zinc oxide crystal constituting the zinc oxide powder of the present invention has a (101) plane peak half-width increase rate of 3.0 times or more when subjected to planetary ball milling under the above-mentioned predetermined conditions, preferably It is 4.0 times or more, More preferably, it is 4.5 to 6.0 times. Such a high half-value width increase rate means that the crystal structure is easily distorted with respect to stress. For example, 100 g of sample powder is put into a planetary ball mill using 99.5% pot (500 ml) of alumina and 400 g of φ10 mm alumina balls (99.9%), and pulverized for 1 hour at a rotation speed of 200 rpm. Can be done to The half-width increase rate of the (101) plane peak was measured in advance by measuring the half-width of the zinc oxide (101) peak using an X-ray diffractometer in the same manner as described above for the crushed sample powder. It can be determined by determining the ratio of the zinc oxide (101) peak before crushing to the half width.

  The zinc oxide crystal constituting the zinc oxide powder of the present invention contains a dopant element and / or oxygen deficiency. The presence of the dopant element and / or oxygen vacancies allows for easy strain as defined by the half-width increase rate described above. That is, in the zinc oxide powder in which the dopant element is dissolved, since atoms having different valences and ionic radii are dissolved, vacancies and strains are formed in the crystal, so that the crystal structure is easily distorted. Similarly, a powder having a large amount of oxygen vacancies is also likely to be easily distorted in crystal structure and lower in crystallinity. Therefore, the type, location and amount of the dopant element and oxygen vacancies are not particularly limited as long as they can give the above-described easy strain. In addition, since zinc oxide powder having high crystallinity before film formation and crystal structure is easily distorted undergoes plastic deformation without being brittle fractured when subjected to stress, it becomes possible to form a film easily. It is thought that the film speed is improved.

  According to a preferred embodiment of the present invention, the zinc oxide crystal contains a dopant element. Preferred examples of the dopant element include aluminum, gallium, indium, titanium, silicon, magnesium, cobalt, lithium, manganese, iron, copper, and any combination thereof, and more preferably aluminum. These dopant elements not only make the crystal structure easily distorted but also improve the conductivity of the zinc oxide coating. The dopant element is preferably solid-dissolved in the zinc oxide particles in an amount of 0.01 to 1 mol%, more preferably 0.1 to 0.8 mol%, still more preferably 0.2 to 0.6 mol%. The zinc oxide powder according to this aspect is prepared by mixing zinc oxide powder as a raw material and a powder of a dopant element-containing compound at a predetermined ratio, firing the obtained mixed powder, and optionally pulverizing the fired powder. Thus, it can be preferably prepared by adjusting the particle size. The mixed powder is preferably fired in the atmosphere at 1100 to 1500 ° C. for 1 to 10 hours, more preferably 1250 to 1500 ° C., and further preferably 1300 to 1450 ° C. In addition, when pulverization is performed after firing, it is preferable to recover the crystallinity reduced by pulverization by heat-treating the powder after pulverization. It is preferably performed for 10 hours.

According to another preferred embodiment of the present invention, the zinc oxide crystal contains oxygen vacancies. Oxygen deficiency is difficult to quantitatively measure, but it is possible to relatively compare the deficit amount by the green emission intensity in the photoluminescence measurement. The zinc oxide powder according to this embodiment can be preferably produced by heat-treating zinc oxide powder as a raw material in a low oxygen atmosphere, and optionally pulverizing the powder after heat treatment to adjust the particle size. Examples of low oxygen atmospheres include vacuum, inert gas, reducing gas, and combinations thereof. Preferable examples of the inert gas include argon and nitrogen. A preferred example of the reducing gas is hydrogen gas. The heat treatment in a low oxygen atmosphere is preferably performed at 900 to 1200 ° C.
In addition, when pulverization is performed after firing, it is preferable to recover the crystallinity reduced by pulverization by heat-treating the powder after pulverization. It is preferably performed for 10 hours.

  According to still another preferred embodiment of the present invention, the zinc oxide crystal may contain both a dopant element and an oxygen vacancy. The production of the zinc oxide powder according to this aspect can be performed by appropriately combining the production method according to the aspect containing the dopant element described above and the production method according to the aspect containing oxygen deficiency.

  The zinc oxide powder according to the present invention preferably has a volume-based D50 average particle diameter of 1.0 μm or more, more preferably 1.5 μm or more, and further preferably 3.0 to 5.0 μm. With such a particle size, the film formation rate in the AD method is improved. This volume reference D50 average particle diameter can be measured by a particle size distribution measuring apparatus.

  In the zinc oxide powder according to the present invention, it is preferable that the powder on the coarse particle side is removed by airflow classification treatment because the film forming speed can be further improved. As a result of the airflow classification process, this improvement in film formation speed is achieved by 1) removing coarse particles that obstruct film formation, 2) homogenizing the film formation particle diameter, and 3) solving powder aggregation. It is thought that it is realized by. The zinc oxide powder obtained by removing the powder on the coarse particle side in this way preferably has a volume-based D95 particle size of 10 μm or less, more preferably 2.0 to 9.0 μm, and even more preferably 4.5 to It has a volume based D95 particle size of 8.0 μm.

  By performing the AD method using the zinc oxide powder according to the present invention as a film forming raw material, a zinc oxide film can be manufactured at a significantly high film forming rate.

  The present invention is more specifically described by the following examples.

Example 1
(1) Production of zinc oxide powder Zinc oxide type 1 powder (manufactured by Shodo Chemical Industry Co., Ltd., volume standard D50: 0.8 μm) and aluminum oxide powder (manufactured by Sumitomo Chemical Co., Ltd., AKP-20 (volume) Standard D50: 0.5 μm)) was weighed so that the molar ratio of aluminum was 0.5 mol%. This mixed powder was wet-mixed in a pot mill using φ2 mm zirconia balls for 24 hours. The obtained mixed powder was fired at 1400 ° C. for 5 hours in the air. Next, the synthesized powder was wet-ground for 4 to 6 hours using a zirconia ball having a diameter of 2 mm in a pot mill so that the volume standard D50 was 2 to 3 μm, more precisely 2.6 μm. After pulverization, the powder was heat-treated in the atmosphere at 950 ° C. to recover the crystallinity lowered by pulverization. Thus, a zinc oxide powder containing 0.5 mol% of aluminum was obtained as a sample powder. When the obtained sample powder was observed with SEM, the image shown in FIG. 3 was obtained.

(2) Evaluation of zinc oxide powder Various evaluations were performed on the obtained sample powder as follows.

Evaluation 1 : Average particle size The particle size distribution of the sample powder was measured by a wet method using a laser diffraction / scattering particle size analyzer (Microtrac MT3300 EXII manufactured by Nikkiso Co., Ltd.), and the volume-based D50 average particle size was determined. The standard D50 average particle size was 2-3 μm, more precisely 2.6 μm, and the volume standard D95 particle size was 81.0 μm.

Evaluation 2 : Crystallinity The crystallinity of the sample powder was measured using an X-ray diffractometer (manufactured by Bruker AX) with a tube current of 40 mA, a tube voltage of 40 kV, a light receiving slit of 0.2 mm, a divergence slit of 0.6 °, a scattering slit of 0.6 °, And it measured on the conditions of solar slit 4 degrees. The crystallinity of the powder was evaluated by measuring the half width of the obtained zinc oxide (101) peak. The full width at half maximum is 1/2 of the maximum value of the peak as shown in FIG. 1 after smoothing, background removal, and Kα2 peak removal for the zinc oxide (101) peak of the XRD profile. It was determined by determining the lateral width when the peak shape was cut at a position where the strength was reached. The result was 0.072 ° as shown in Table 1.

Evaluation 3 : Easy distortion In order to evaluate the ease of distortion of the crystal of the sample powder, the sample powder was pulverized by a planetary ball mill. Specifically, 100 g of the sample powder was put into a planetary ball mill using 99.5% pot (500 ml) of alumina and 400 g of φ10 mm alumina balls (99.9%), and pulverized for 1 hour at a rotation speed of 200 rpm. When the half width of the zinc oxide (101) peak was measured for the crushed sample powder using an X-ray diffractometer in the same manner as in Evaluation 2, it was 0.346 ° as shown in Table 1. This value was 4.8 times the half width of 0.072 ° obtained in Evaluation 2, and the half width was significantly increased before and after the planetary ball mill treatment.

(3) Production of Zinc Oxide Film by AD Method Using the obtained sample powder, a zinc oxide film was produced by the film forming apparatus 20 shown in FIG. A film forming apparatus 20 shown in FIG. 2 is configured as an apparatus used for the AD method in which a raw material powder is injected onto a substrate in an atmosphere at a pressure lower than atmospheric pressure. The film forming apparatus 20 includes an aerosol generating unit 22 that generates an aerosol of a raw material powder containing a raw material component, and a film forming unit 30 that sprays the raw material powder onto a substrate 21 to form a film containing the raw material component. . The aerosol generation unit 22 contains a raw material powder, receives an supply of a carrier gas from a gas cylinder (not shown), generates an aerosol, a raw material supply pipe 24 that supplies the generated aerosol to the film forming unit 30, and An aerosol generation chamber 23 and a vibrator 25 that applies vibration to the aerosol in the aerosol generation chamber 23 at a frequency of 10 to 100 Hz are provided. The film forming unit 30 includes a film forming chamber 32 that injects aerosol onto the substrate 21, a substrate holder 34 that is disposed inside the film forming chamber 32 and fixes the substrate 21, and the substrate holder 34 in the X axis-Y axis direction. And an XY stage 33 that moves. The film forming unit 30 includes a spray nozzle 36 that has a slit 37 formed at the tip thereof and sprays aerosol onto the substrate 21, and a vacuum pump 38 that decompresses the film forming chamber 32. The film forming apparatus 20 may be configured to heat the raw material powder by providing a heating device, a heat-resistant member, or the like in the film forming chamber 32. For example, a heat-resistant member such as quartz glass or ceramics may be used so that heat treatment can be performed at a temperature at which the raw material powder is single-crystallized.

  The conditions for producing the zinc oxide film by the film forming apparatus 20 were as follows. As the substrate, a ZnO single crystal substrate (10 mm × 10 mm square, thickness 0.5 mm, c-plane) was used. Further, nitrogen gas having a flow rate of 6 L / min is used as a carrier gas, and the pressure in the film forming chamber is adjusted to 0.1 to 0.2 kPa, and the pressure in the aerosol chamber is adjusted to 50 to 70 kPa to form a film. Went. At that time, the opening size of the nozzle was 10 × 0.8 mm, and scanning was performed simultaneously with the film formation for 60 reciprocations at a scanning distance of 12 mm and a scanning speed of 1 mm / sec in the short side direction of the nozzle. In this way, a zinc oxide film was obtained.

(4) Evaluation of film formation speed During the film formation, a part of the substrate is masked to form a film forming part and a non-film forming part on the substrate. The thickness of the zinc oxide film was determined by measuring the step. The film thickness was measured using a small shape roughness measuring machine (Taylor-Hobson, “Form Talysurf plus”). The formed zinc oxide film had a thickness of 14 μm. As will be described later, by forming zinc oxide films on various samples under the same film formation conditions, and measuring and comparing the film thicknesses, the film formation rate can be relatively evaluated. That is, when the film formation conditions are the same, it can be evaluated that the film formation rate is higher as the film thickness is larger.

Example 2
A zinc oxide powder was produced and evaluated in the same manner as in Example 1 except that the blending ratio of the aluminum oxide powder was changed. The obtained sample powder was a zinc oxide powder containing 0.4 mol% of aluminum and having a volume-based D50 average particle diameter of 2 to 4 μm, more precisely 2.6 μm. When this sample powder was used for film formation under the same conditions as in Example 1, a zinc oxide film having a thickness of 6 μm was obtained. Moreover, when the half width of the zinc oxide (101) peak was measured on the sample powder before and after planetary ball milling in the same manner as in Example 1, it was 0.082 ° before milling and 0.328 ° after milling. Thus, the full width at half maximum increased by 4.0 times before and after milling.

Example 3
A zinc oxide powder was produced and evaluated in the same manner as in Example 1 except that the blending ratio of the aluminum oxide powder was changed. The obtained sample powder was zinc oxide powder containing 0.2 mol% of aluminum and having a volume-based D50 average particle diameter of 2 to 4 μm, more precisely 2.6 μm. When this sample powder was used to form a film under the same conditions as in Example 1, a zinc oxide film having a thickness of 2 μm was obtained. Further, when the half width of the zinc oxide (101) peak was measured on the sample powder before and after the planetary ball milling in the same manner as in Example 1, it was 0.102 ° before milling and 0.316 ° after milling. Thus, the full width at half maximum increased 3.1 times before and after milling.

Example 4 (Comparison)
Zinc oxide powder was prepared and evaluated in the same manner as in Example 1 except that the crystallinity was not recovered by heat treatment at 950 ° C. in the air. The obtained sample powder was a zinc oxide powder containing 0.5 mol% of aluminum and having a volume-based D50 average particle diameter of 2 to 4 μm, more precisely 2.6 μm. When this sample powder was used to form a film under the same conditions as in Example 1, a zinc oxide film having a thickness of 0.2 μm was obtained. Further, when the half width of the zinc oxide (101) peak was measured on the sample powder before and after the planetary ball milling in the same manner as in Example 1, it was 0.161 ° before the milling and 0.323 ° after the milling. Thus, the full width at half maximum increased 2.0 times before and after milling.

Example 5 (Comparison)
Zinc oxide powder was prepared and evaluated in the same manner as in Example 1 except that no aluminum oxide was added. The obtained sample powder was a zinc oxide powder not doped with a different element and having an average particle diameter of 2 to 4 μm, more precisely 2.6 μm. When this sample powder was used to form a film under the same conditions as in Example 1, a zinc oxide film having a thickness of 0.2 μm was obtained. Further, when the half width of the zinc oxide (101) peak was measured on the sample powder before and after planetary ball milling in the same manner as in Example 1, it was 0.098 ° before milling and 0.248 ° after milling. Thus, the full width at half maximum increased 2.5 times before and after milling.

Example 6 (Comparison)
Zinc oxide powder was prepared and evaluated in the same manner as in Example 5 except that the heat treatment temperature for crystallinity recovery was 700 ° C. The obtained sample powder was a zinc oxide powder not doped with a different element and having an average particle diameter of 2 to 4 μm, more precisely 2.6 μm. Using this sample powder, film formation was attempted under the same conditions as in Example 1, but film formation was impossible. Further, when the half width of the zinc oxide (101) peak was measured on the sample powder before and after the planetary ball milling in the same manner as in Example 1, it was 0.125 ° before milling and 0.225 ° after milling. Thus, the full width at half maximum increased 1.8 times before and after milling.

Example 7 (Comparison)
Commercially available zinc oxide powder (manufactured by Sakai Chemical Industry Co., Ltd., LP-ZINC5) in a pot mill using zirconia balls with a diameter of 2 mm so that the volume standard D50 is 2 to 3 μm, more precisely 2.6 μm. Wet milled for hours. The obtained sample powder has not been subjected to crystallinity recovery by heat treatment, and is a zinc oxide powder not doped with a different element and having an average particle diameter of 2 to 3 μm, more precisely 2.6 μm. . Using this sample powder, film formation was attempted under the same conditions as in Example 1, but film formation was impossible. Further, when the half width of the zinc oxide (101) peak was measured on the sample powder before and after the planetary ball milling in the same manner as in Example 1, it was 0.184 ° before milling and 0.254 ° after milling. Thus, the full width at half maximum increased 1.4 times before and after milling.

Example 8 : Airflow classification treatment of powder The airflow classification treatment was performed on the powder obtained by heat treatment in Example 1. This air flow classification treatment was performed using a precision air classifier (Nisshin Engineering Co., Ltd., TURBO CLASSIFIER TC-15NSC) under conditions of an air volume of 2.5 m ³ / min and a rotor rotational speed of 5460 rpm. Of the classified powders, the particle size distribution measurement was performed on the fine powder side powder with a laser diffraction / scattering particle size analyzer. As a result, coarse particles slightly contained in Example 1 were removed, and the volume-based D50 average was removed. The particle size was 2.4 μm, and the volume standard D95 particle size was 5.0 μm. FIG. 4 shows an SEM image of the powder from which coarse particles have been removed. When this sample powder was used to form a film under the same conditions as in Example 1, a zinc oxide film having a thickness of 18 μm was obtained. Since this film thickness is thicker than the film according to Example 1 (thickness: 14 μm), it can be seen that the film formation speed is further improved by using the powder from which coarse particles have been removed by the airflow classification process. Further, the half width of the zinc oxide (101) peak was measured on the sample powder before and after planetary ball milling in the same manner as in Example 1. As shown in Table 2, 0.071 ° before milling, After the treatment, it was 0.345 °, and the half-value width increased 4.9 times before and after the mill treatment.

Example 9 : Powder airflow classification treatment As in Example 8, except that the pulverization time by a pot mill is 3 to 4 hours, and the volume-based D50 average particle diameter after powder heat treatment and airflow classification is 3.5 μm. The zinc oxide powder was prepared and evaluated. This powder had a volume-based D95 particle size of 7.8 μm and contained almost no coarse particles of 10 μm or more. When this sample powder was used to form a film under the same conditions as in Example 1, a zinc oxide film having a thickness of 22 μm was obtained. Since this film thickness is thicker than the film according to Example 1 (thickness: 14 μm), it can be seen that the film formation speed is further improved by using the powder from which coarse particles have been removed by the airflow classification process. Further, when the half width of the zinc oxide (101) peak was measured on the sample powder before and after planetary ball milling in the same manner as in Example 1, it was 0.079 ° before milling and 0.335 ° after milling. Thus, the full width at half maximum increased 4.2 times before and after milling.

Example 10
Preparation and evaluation of zinc oxide powder were carried out in the same manner as in Example 8, except that the grinding time by the pot mill was 10 to 12 hours, and the volume-based D50 average particle size after powder heat treatment and airflow classification was 1.2 μm. It was. The volume-based D95 particle size of this powder was 3.7 μm, and coarse particles of 10 μm or more were hardly contained from SEM observation. When this sample powder was used to form a film under the same conditions as in Example 1, a 4 μm thick zinc oxide film was obtained. Further, when the half width of the zinc oxide (101) peak was measured on the sample powder before and after the planetary ball milling in the same manner as in Example 1, it was 0.096 ° before milling and 0.302 ° after milling. Thus, the full width at half maximum increased 3.1 times before and after milling.

Example 11 (Comparison)
Zinc oxide powder was prepared and evaluated in the same manner as in Example 10 except that the airflow classification treatment was not performed. This powder had a volume-based D50 average particle size of 1.7 μm and a volume-based D95 particle size of 88.9 μm, which contained a small amount of coarse particles. When this sample powder was used to form a film under the same conditions as in Example 1, a zinc oxide film having a thickness of 1.5 μm was obtained. Further, when the half width of the zinc oxide (101) peak was measured on the sample powder before and after planetary ball milling in the same manner as in Example 1, it was 0.104 ° before milling and 0.304 ° after milling. Thus, the full width at half maximum increased 2.9 times before and after milling.

Example 12 (Comparison)
Zinc oxide powder was prepared and evaluated in the same manner as in Example 10 except that the crystallinity was not recovered by heat treatment at 950 ° C. in the air. This powder had a volume-based D50 average particle size of 1.2 μm, and a volume-based D95 particle size of 2.9 μm and almost no coarse particles of 10 μm or more. Using this sample powder, film formation was attempted under the same conditions as in Example 1, but film formation was impossible. Further, when the half width of the zinc oxide (101) peak was measured on the sample powder before and after planetary ball milling in the same manner as in Example 1, it was 0.195 ° before milling and 0.308 ° after milling. Thus, the full width at half maximum increased 1.6 times before and after milling.

DESCRIPTION OF SYMBOLS 20 Film-forming apparatus 21 Substrate 22 Aerosol production | generation part 23 Aerosol production | generation chamber 24 Raw material supply pipe 25 Exciter 30 Film-forming part 32 Film-forming chamber 33 XY stage 34 Substrate holder 36 Injection nozzle 37 Slit 38 Vacuum pump

Claims (14)

A zinc oxide powder used as a film forming raw material in an aerosol deposition method, the zinc oxide powder comprising a plurality of zinc oxide particles comprising zinc oxide crystals containing a dopant element and / or oxygen deficiency;
The zinc oxide crystals are
Crystallinity defined by the half width of the zinc oxide (101) plane peak in X-ray diffraction being 0.11 ° or less;
Easily distorted as defined by the fact that the half-width of the (101) plane peak increases to a value of 3.0 times or more when pulverization by a planetary ball mill using an alumina pot and alumina balls is performed at 200 rpm for 1 hour. And zinc oxide powder.   The zinc oxide powder according to claim 1, wherein the crystallinity is defined by a half width of a zinc oxide (101) plane peak in X-ray diffraction being 0.08 ° or less.   When the pulverization by a planetary ball mill using an alumina pot and an alumina ball is performed at 200 rpm for 1 hour, the half-width of the (101) plane peak increases to a value of 4.0 times or more. The zinc oxide powder according to claim 1 or 2, which is defined.   4. The device according to claim 1, wherein the dopant element is at least one element selected from the group consisting of aluminum, gallium, indium, titanium, silicon, magnesium, cobalt, lithium, manganese, iron, and copper. Zinc oxide powder according to Item.   The zinc oxide powder according to any one of claims 1 to 4, wherein the dopant element is aluminum.   The zinc oxide powder according to any one of claims 1 to 5, wherein the dopant element is solid-dissolved in the zinc oxide particles in an amount of 0.01 to 1 mol%.   The oxygen deficiency is generated by heat treatment in a low oxygen atmosphere composed of at least one selected from the group consisting of a vacuum, an inert gas, and a reducing gas. Zinc oxide powder described in 1.   The zinc oxide powder according to claim 7, wherein the heat treatment is performed at 900 to 1200 ° C.   The zinc oxide powder according to any one of claims 1 to 8, wherein the volume-based D50 average particle diameter is 1.0 µm or more.   The zinc oxide powder according to any one of claims 1 to 9, wherein the volume-based D50 average particle diameter is 3.0 to 5.0 µm.   The zinc oxide powder as described in any one of Claims 1-10 by which the powder by the side of a coarse particle is removed by the airflow classification process.   The zinc oxide powder according to any one of claims 1 to 10, wherein the volume-based D95 particle size is 10 µm or less.   The manufacturing method of the zinc oxide film by the aerosol deposition method using the zinc oxide raw material powder as described in any one of Claims 1-12.   Use of the zinc oxide raw material powder according to any one of claims 1 to 12 as a film forming raw material in an aerosol deposition method.