JPH10182290A - Ultraviolet-ray detecting element and detection of ultraviolet rays, using the same - Google Patents

Ultraviolet-ray detecting element and detection of ultraviolet rays, using the same

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Publication number
JPH10182290A
JPH10182290A JP34169796A JP34169796A JPH10182290A JP H10182290 A JPH10182290 A JP H10182290A JP 34169796 A JP34169796 A JP 34169796A JP 34169796 A JP34169796 A JP 34169796A JP H10182290 A JPH10182290 A JP H10182290A
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zinc oxide
crystal
ultraviolet
electric field
axis
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Japanese (ja)
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Satoru Fujizu
Fumitaka Ishimori
史高 石森
悟 藤津
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Sekisui Plastics Co Ltd
積水化成品工業株式会社
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Abstract

PROBLEM TO BE SOLVED: To provide the novel detecting element which employs zinc oxide as an ultraviolet-sensitive material and has higher sensitivity to ultraviolet rays as compared with a conventional element and also to provide the detection of ultraviolet rays, using this detecting element.
SOLUTION: In this ultraviolet detector element 1, the (a) plane of a crystal or polycrystal of single crystal zinc oxide or polycrystalline zinc oxide having oriented crystallographic axes is used as a photoreceptive surface 11a to be irradiated with ultraviolet rays. Also, the element 1 is preferably provided with electrodes 12 and 13 for applying an electric field in the direction of the (c) axis, i.e., piezoelectric axis of the zinc oxide crystal (or polycrystal). This detection comprises measuring a change in impedance of the zinc oxide crystal (or polycrystal) while applying an electric field having frequency equivalent to the antiresonant frequency in the piezoelectric effect to the crystal (or polycrystal) between the electrodes 12 and 13.
COPYRIGHT: (C)1998,JPO

Description

【発明の詳細な説明】 DETAILED DESCRIPTION OF THE INVENTION

【0001】 [0001]

【発明の属する技術分野】この発明は、酸化亜鉛の光導電効果を利用した紫外線検出素子と、それを用いた紫外線検出方法に関するものである。 BACKGROUND OF THE INVENTION This invention provides an ultraviolet detector element utilizing photoconductive effect of the zinc oxide, it relates to an ultraviolet detection method using the same.

【0002】 [0002]

【従来の技術】近時、酸化亜鉛の光学的禁止帯幅(E [Description of the Related Art In recent years, the optical band gap of zinc oxide (E
opt )が紫外部にあって、波長400nm以下の紫外線の照射によって光導電効果を示すとともに、可視光に対しては実質的に透明でほとんど光感受性を有しないことを利用して、上記酸化亜鉛を紫外線感受材料として使用した紫外線検出素子が提案された(特開平3−2417 opt) is in the ultraviolet region, with showing a photoconductive effect by irradiation of ultraviolet light having a wavelength of at most 400 nm, by utilizing the fact that have little light sensitive substantially transparent to visible light, the zinc oxide the UV detection element is proposed which is used as an ultraviolet sensitive material (JP-a-3-2417
77号公報)。 77 JP).

【0003】かかる紫外線検出素子は、従来の、可視光にも応答してしまう素子と比べて、バンドパスフィルタ等の、可視光をカットするための光学部品を必要としないなどの利点があるとされている。 [0003] Such UV detection element of a conventional, as compared to the elements and may respond to visible light, such as a band-pass filter, if there is an advantage such does not require optical components for cutting visible light It is. 上記紫外線検出素子は、基板上に、気相成長法による酸化亜鉛の薄膜と、この薄膜の、光導電効果による抵抗値の変化を抽出する電極とを形成したものである。 The UV detector elements on a substrate, a thin film of zinc oxide by the vapor phase growth method, the thin film is obtained by forming an electrode for extracting the change in the resistance value due to photoconductive effect.

【0004】 [0004]

【発明が解決しようとする課題】上に述べた先願公報の説明によると酸化亜鉛の薄膜は、その光学的禁止帯幅(E opt )がおよそ3.0〜3.2eVの範囲にあるのが好ましいとされている。 The thin film of zinc oxide according to the description of the prior application publications described above [0008], the optical band gap (E opt) is in the range of approximately 3.0~3.2eV It is that there is preferable. ところが発明者らの検討によると、その禁止帯幅が3.0eVである半導体においては、感度域の長波長側が、可視光領域である波長412 However, according to the study by the inventors, in the semiconductor its band gap is 3.0 eV, the long wavelength side of the sensitivity range, wavelength 412 is visible light region
nmの付近まで達するため、光学的禁止帯幅が上記の範囲にある先願公報の素子は、従来のものほどではないにしろ、やはり可視光にも感度を有しており、それが原因で、紫外線に対する感度が不十分になるおそれのあることが明らかとなった。 To reach up to the vicinity of nm, elements of the prior application publication optical band gap is in the range described above, if not as much as the conventional, and also has sensitivity to visible light, it causes , it was revealed that a risk of sensitivity to ultraviolet light becomes insufficient.

【0005】この発明の目的は、紫外線感受材料として酸化亜鉛を使用して、なおかつ従来に比べて紫外線に対する感度が高い、新規な紫外線検出素子と、それを用いた紫外線検出方法とを提供することにある。 An object of the present invention uses zinc oxide as an ultraviolet sensitive material, yet conventionally sensitive to ultraviolet light than the, to provide a novel UV detection element, an ultraviolet detection method using the same It is in.

【0006】 [0006]

【課題を解決するための手段】上記課題を解決するため、発明者らは、酸化亜鉛の結晶構造と、紫外線に対する感度との関係について種々検討を行った。 In order to solve the above problems SUMMARY OF THE INVENTION The inventors have conducted a crystal structure of zinc oxide, various studies on the relationship between the sensitivity to ultraviolet light. その結果、 as a result,
酸化亜鉛の代表的な結晶構造であるウルツ鉱型構造においては、紫外線照射による光導電効果に結晶軸異方性があり、前述した先願公報における酸化亜鉛の薄膜では、 In wurtzite structure is a typical crystal structure of zinc oxide, there are crystal axis anisotropic photoconductive effect by ultraviolet irradiation, a thin film of zinc oxide in the prior application publication mentioned above,
受光面である薄膜の表面が結晶のc面、あるいはアモルファスの薄膜の場合はランダムな面となり、また酸化亜鉛の微粉を焼結したブロックの場合には、やはり受光面がランダムな面となるが、これらの面に代えて結晶のa If the surface of the thin film is a light receiving surface of a thin film of the c-plane, or an amorphous crystal becomes random surface, in the case of blocks obtained by sintering fine powder of zinc oxide, but also the light receiving surface is random surface , a crystal instead of these surfaces
面を受光面とすると、紫外線に対する感度をこれまでよりも向上できることを見出し、この発明を完成するに至った。 When the surface as a light-receiving surface, the sensitivity to ultraviolet radiation found can be improved than ever, and have completed the present invention.

【0007】したがってこの発明の紫外線検出素子は、 Accordingly ultraviolet detector of the present invention,
酸化亜鉛の、紫外線照射による光導電効果を利用したものであって、単結晶、または結晶軸配向性を有する多結晶の酸化亜鉛の、結晶のa面を受光面としたことを特徴としている。 Of zinc oxide, be one obtained by utilizing a photoconductive effect by ultraviolet irradiation, the zinc oxide polycrystalline having a single crystal, or the crystal axis orientation, and characterized in that the light-receiving plane of a face of the crystal. 上記のように結晶のa面を受光面とした場合に、従来に比べて紫外線に対する感度が向上するのは、後述する実施例の結果より明らかなように、光導電効果の中心が短波長側、つまり紫外線側にシフトし、それに伴って素子の感度域も紫外線側にシフトするのが原因であると考えられる。 When the a-plane of the crystal as described above and the light-receiving surface, to increase sensitivity to ultraviolet light as compared with the prior art, as is clear from the results of Examples described later, the center of the photoconductive effect is short wavelength side , i.e. shifted to UV side, the sensitivity range of the device with it also believed to be caused to shift to the UV side.

【0008】なお、上述したこの発明の紫外線検出素子においては、光導電効果による抵抗値の変化を抽出する電極として、結晶の圧電軸であるc軸の方向に電場を印加する電極を設けるのが好ましい。 [0008] In the ultraviolet detector of the present invention described above, as an electrode for extracting a change in the resistance value due to photoconductive effect, to dispose an electrode for applying an electric field in the direction of the c-axis is a piezoelectric axis of the crystal preferable. かかる構成とすると、やはり後述する実施例の結果より明らかなように、 In such a configuration, as also apparent from the results of Examples appearing later,
電極に印加する電場の強度を調整することによって、光導電効果の強度と、その中心波長とを変化させることが可能となる。 By adjusting the intensity of the electric field applied to the electrodes, it is possible to vary the intensity of the photoconductive effect, and its center wavelength.

【0009】また、上記のように結晶のa面を受光面とし、かつ結晶の圧電軸であるc軸の方向に電場を印加する電極を設けた紫外線検出素子を用いて紫外線検出を行う場合には、上記電極に、酸化亜鉛の結晶の、圧電効果における反共振周波数に相当する周波数の電場を印加しつつ、当該結晶の光導電効果に基づくインピーダンスの変化を測定するのが好ましい。 Further, in the case of a UV detector using a ultraviolet ray detection element provided with electrodes for applying an electric field in the direction of the c-axis is a piezoelectric axis of the a-plane of the crystal as described above and the light-receiving surface, and crystal is to the electrode, the crystals of zinc oxide, while applying an electric field of a frequency corresponding to the anti-resonance frequency in the piezoelectric effect, it is preferable to measure changes in impedance based on the photoconductive effect of the crystal.

【0010】光導電効果に基づく酸化亜鉛の結晶のインピーダンス変化は、電極に印加する電場の周波数が高いほど、その矩形性は向上するが変化量が小さくなり、逆に周波数が低いほど、その変化量は大きくなるが矩形性が低下する傾向を示す。 [0010] impedance change of the crystal of the zinc oxide based on the photoconductive effect, the higher the electric field frequency applied to the electrode, its rectangularity is but variation is reduced enhancing, the lower the frequency the contrary, the change the amount increases but shows a tendency rectangle is lowered. ところが、上記のように電極に印加する電場の周波数を反共振周波数とした場合には、 However, when the frequency of the electric field applied to the electrodes as described above and the anti-resonant frequency,
これも後述する実施例の結果より明らかなように、特異的に、酸化亜鉛の結晶のインピーダンス変化を、良好な矩形性を維持しつつ、その変化量も十分に大きい状態とすることができるため、インピーダンス変化の測定が容易となる。 As also apparent from the results of Examples described later, specifically, the impedance change of the crystal of the zinc oxide, while maintaining good rectangularity, it is possible to the amount of change even large enough state , it is easy to measure the impedance change.

【0011】 [0011]

【発明の実施の形態】以下にこの発明を、その実施の形態の一例を示す図面を参照しつつ説明する。 DETAILED DESCRIPTION OF THE INVENTION The present invention will now be described with reference to the drawings showing an example of the embodiment. 図1は、この発明の紫外線検出素子の一例を示す斜視図である。 Figure 1 is a perspective view showing an example of the ultraviolet detector of the present invention. 同図にみるようにこの例の紫外線検出素子1は、紫外線感受材料として、酸化亜鉛の結晶からなる直方体状のブロック11を用いるとともに、このブロック11の互いに平行な2面に、光導電効果による抵抗値の変化を抽出するための、一対の電極12、13を形成したものである。 UV detection element 1 of this embodiment as seen in the drawing, the ultraviolet sensitive material, with use of the rectangular block 11 made of crystals of zinc oxide, the two parallel surfaces each other of the block 11, by photoconductive effect for extracting a change in resistance value, and forming a pair of electrodes 12 and 13.

【0012】ブロック11の受光面11aは、前述したように酸化亜鉛の結晶のa面に相当している。 [0012] the light-receiving surface 11a of the block 11 is equivalent to a surface of the crystal of the zinc oxide as described above. また図の例では、結晶のc軸の方向(図1中に実線の矢印cで示す)に電場を印加すべく、一対の電極12、13が、上記c軸の方向と直交する互いに平行な2面(c面)に形成されている。 In the illustrated example, in order to apply an electric field in the direction of the c axis of the crystal (shown by a solid line arrow c in FIG. 1), a pair of electrodes 12 and 13, parallel to each other perpendicular to the direction of the c-axis It is formed in the two surfaces (c plane). 上記ブロック11を構成する酸化亜鉛の結晶としては単結晶、または結晶軸配向性を有する多結晶のものが採用される。 The crystalline zinc oxide constituting the block 11 as polycrystalline having a single crystal, or the crystal axis orientation can be employed.

【0013】なお、結晶軸配向性を有する多結晶の酸化亜鉛とは、X線回折において、結晶の(103)面に対応するピークの強度と、(004)面に対応するピークの強度との比I (103) /I (004)が1.0以下で、多結晶を構成する結晶粒がc軸方向に配向したものをいう。 [0013] Note that the zinc oxide polycrystalline having a crystal axis orientation, the X-ray diffraction, of the intensity of the peak corresponding to the (103) plane of the crystal, and the intensity of the peak corresponding to the (004) plane the ratio I (103) / I (004 ) is 1.0 or less, it refers to those crystal grains constituting the polycrystalline is oriented in the c-axis direction.
かかる、結晶軸配向性を有する多結晶の酸化亜鉛は、たとえば発明者のうち藤津が特開平5−70286号公報において提案した、酸化亜鉛を還元性雰囲気中で昇華させ、ついでこの還元性気体を、それよりも低温に保持された回転する基体と接触させて、当該基体上に酸化亜鉛の結晶を析出させる製造方法、いわゆる気相輸送法によって製造される。 Such zinc oxide polycrystalline having a crystal axis orientation, for example of the invention's Fujitsu has proposed in Japanese Patent Laid-Open 5-70286 discloses, zinc oxide is sublimed in a reducing atmosphere, then the reducing gas , and it is contacted with a substrate rotating held in a temperature lower than a manufacturing method for precipitating crystals of zinc oxide on the substrate, is manufactured by a so-called vapor-phase transport method.

【0014】上記の気相輸送法によれば、肉厚で比較的大きく、かつ均質でクラック等のない酸化亜鉛の結晶を高速度で製造できるとともに、製造された酸化亜鉛の結晶は、上記のごとく多結晶でありながらその結晶粒のほぼ100%がc軸方向に配向しており、光導電効果や圧電効果の点からすると単結晶とほぼ等しい特性を有するものとなる。 According to vapor transport method described above, a relatively large wall thickness, and with the crystal without zinc oxide of cracks in a homogeneous can be produced at a high speed, the produced zinc oxide crystals, of the as almost 100% of the grains with a polycrystalline are oriented in the c-axis direction, from the viewpoint of photoconductive effect or a piezoelectric effect as having substantially equal characteristics as the single crystal.

【0015】一方、単結晶構造の酸化亜鉛は、たとえば特開平6−122595号公報に開示された、酸化亜鉛を溶解させたアルカリ溶液を育成容器に注入して、水熱条件下で結晶成長させる方法等、従来公知の種々の方法により製造できる。 Meanwhile, the zinc oxide single crystal structure, for example, disclosed in Japanese Patent Laid-Open No. 6-122595, by injecting an alkaline solution prepared by dissolving zinc oxide in growth vessel, it is grown under hydrothermal conditions the method or the like, can be produced by various conventionally known methods. そして、上記のようにして製造された単結晶または多結晶の酸化亜鉛を、その結晶のa面が受光面11aとなり、かつ結晶のc軸と直交する互いに平行な2面のc面が、一対の電極12、13が形成される面となるように直方体状に切り出した後、さらに必要に応じてその表面を研磨すれば、前述した酸化亜鉛のブロック11が製造される。 Then, the zinc oxide of the above manner single crystal manufactured or polycrystalline, a surface light-receiving surface 11a next to the crystal, and the c-plane of the mutually parallel two surfaces perpendicular to the c axis of the crystal, the pair after the electrodes 12 and 13 is cut into a rectangular shape so that the plane formed, if polishing the surface if necessary, block 11 of zinc oxide as described above is manufactured.

【0016】なお、前記の方法で製造された単結晶または多結晶の酸化亜鉛は、原料の純度等にもよるが、その抵抗率が数Ωcm程度の高純度の酸化亜鉛の結晶となって、そのままでは紫外線感受材料として使用できない場合が多い。 [0016] Incidentally, the zinc oxide of the single crystal produced by the method or polycrystalline, depending on the raw material purity, etc., becomes the resistivity of the high purity zinc oxide of about several Ωcm crystals, as is in many cases can not be used as an ultraviolet-sensitive material. そこでこの場合には、上記のようにして切り出したブロック11に、たとえばリチウム、ナトリウム、カリウム等の1価の元素を拡散させて高抵抗化するのが好ましい。 So in this case, the block 11 cut out as described above, for example lithium, sodium, that a high resistance by diffusing a monovalent elements such as potassium preferred.

【0017】たとえばリチウムを拡散させるには、まず前記のように直方体状に切り出し、さらに必要に応じてその表面を研磨したブロック11の表面に、浸漬法等によって炭酸リチウム等のリチウム化合物の水溶液を塗布した後、乾燥させる。 [0017] For example, to diffuse lithium, the cut into a rectangular shape as firstly, to the surface of the block 11 that polishing the surface if necessary, an aqueous solution of lithium compound such as lithium carbonate, and dip method after coating, drying. つぎにこのブロック11を、空気中でおよそ700〜800℃程度の温度で10〜100 Next, this block 11, at a temperature of about approximately 700 to 800 ° C. in air from 10 to 100
0時間、加熱すると、リチウムがほぼ均等に熱拡散されて、ブロック11が、抵抗率およそ1GΩcm以上に高抵抗化される。 0 hours, when heated, lithium is substantially uniformly heat spreading, block 11 is high resistance above approximately resistivity 1Jiomegacm.

【0018】上記ブロック11の、互いに平行な2面のc面に形成される一対の電極12、13としては、たとえば金、白金、銀、銅、クロム、ニッケル、アルミニウム等の種々の金属材料や、あるいはその2種以上の合金等があげられる。 [0018] of the block 11, as the pair of electrodes 12 and 13 formed on the c-plane of the two parallel sides each other, such as gold, platinum, silver, copper, chromium, nickel, various metallic materials such as aluminum Ya , or two or more alloys, and the like thereof. つぎに、この発明の紫外線検出方法について説明する。 Next, a description will be given UV detection method of the present invention. かかる紫外線検出方法は、たとえば上記図1の紫外線検出素子1の、一対の電極12、13間に、酸化亜鉛の結晶のブロック11の、圧電効果における反共振周波数に相当する周波数の電場を印加しつつ、 Such UV detection methods, for example UV detection element 1 of FIG. 1, between the pair of electrodes 12 and 13, the block 11 of the crystal of zinc oxide, application of an electric field of a frequency corresponding to the anti-resonance frequency in the piezoelectric effect while,
受光面11aに照射された紫外線による、当該ブロック11の、光導電効果に基づくインピーダンスの変化を測定する方法である。 By ultraviolet rays irradiated on the light receiving surface 11a, of the block 11, a method for measuring changes in impedance based on the photoconductive effect.

【0019】上記反共振周波数は、当該ブロック11の寸法形状により一義的に規定される。 [0019] The anti-resonant frequency is uniquely defined by the dimensions of the block 11. つまり図1のごとく直方体状のブロック11の場合には直方体の各辺の長さにより、固有の反共振周波数が求められる。 That is, when the rectangular parallelepiped block 11 as in FIG. 1 by the length of each side of a rectangular parallelepiped, it obtained a unique anti-resonance frequency. 一対の電極12、13間に、上記反共振周波数の電場を印加するとともに、酸化亜鉛のブロック11の、光導電効果に基づくインピーダンスの変化を測定するためには、たとえばLCRメータ等の、従来公知の種々の回路装置が使用できる。 Between the pair of electrodes 12 and 13, while applying an electric field of the anti-resonance frequency, the block 11 of zinc oxide, in order to measure changes in impedance based on the photoconductive effect, for example, such as an LCR meter, conventional various circuit device can be used for.

【0020】なおこの発明は、以上で説明した例には限定されない。 [0020] Note that this invention is not limited to the examples described above. たとえば図1の例では、酸化亜鉛の結晶を、直方体状のブロック11として使用していたが、酸化亜鉛の結晶の形状は、上記直方体状には限定されず、 For example, in the example of FIG. 1, crystals of zinc oxide, had been used as a rectangular block 11, the crystal shape of the zinc oxide is not limited to the above rectangular shape,
結晶のa面が受光面となりうる種々の形状とすることができる。 Can be a surface of the crystal is various shapes which can be a light-receiving surface. また、酸化亜鉛の結晶のc軸方向に電場を印加するための電極は、上に述べた酸化亜鉛の結晶の形状にあわせて、c軸方向に電場を印加しうる適宜の面に形成すればよい。 Moreover, the electrodes for applying an electric field to the c-axis direction of the crystal of zinc oxide, in accordance with the shape of the crystals of the zinc oxide mentioned above, by forming an appropriate surface capable of applying an electric field to the c-axis direction good.

【0021】その他、この発明の要旨を変更しない範囲で、種々の設計変更を施すことができる。 [0021] Other, within a range not changing the gist of the present invention can be subjected to various modifications.

【0022】 [0022]

【実施例】 【Example】

(結晶軸配向性を有する多結晶の酸化亜鉛の製造)前述した特開平5−70286号公報に所載の気相輸送法に則って、以下の手順により、結晶軸配向性を有する多結晶の酸化亜鉛を製造した。 (Preparation of the zinc oxide polycrystalline having a crystal axis orientation) in accordance with the vapor transport method Shosai in JP-A 5-70286 Patent Publication described above, according to the following procedure, the polycrystal having a crystal axis orientation to produce a zinc oxide. すなわちまず、図2に示すように、原料である酸化亜鉛の焼結体2を、内径24mm That is, first, as shown in FIG. 2, the zinc oxide as a raw material a sintered body 2, inner diameter 24mm
の管状炉31中の、周囲にヒータ32が配置された高温加熱領域にセットするとともに、図中白矢印で示す還元性ガスの流路の下流側(図では右側)に設けた回転軸3 In tube furnace 31, as well as set the high temperature heating region where the heater 32 is arranged around the rotation shaft 3 which is provided (right side in the figure) downstream of the flow path of the reducing gas shown in the drawing the white arrow
3の先端に、基体としての酸化亜鉛の焼結体4(円盤状で、直径12mm、厚み5mm)を、円盤の盤面が上記高温加熱領域に向き合うように取り付けた。 3 of the tip, a sintered body of zinc oxide as a substrate 4 (in disk shape, a diameter of 12 mm, thickness 5mm) and board of the disk is mounted so as to face to the high-temperature heating region.

【0023】つぎに上記焼結体4を、回転軸33とともに図示しない駆動装置によって、図中実線の矢印で示すように0.2r. [0023] then the sintered body 4, by an unillustrated driving means together with the rotating shaft 33, as indicated by arrows in solid line in FIG. 0.2 R. p. p. m. m. の回転速度で回転させつつ、 While rotating at a rotational speed,
また管状炉31内に、還元性ガスであるN 2 −H 2混合ガス(H 2含量6%)を、10〜50cc/分の流速で、図中白矢印で示す流路の方向に流通させながら、ヒータ32に通電して昇温を開始した。 The tubular furnace 31, which is a reducing gas N 2 -H 2 mixture gas (H 2 content 6%), at a flow rate of 10~50Cc / min, is circulated in the direction of the flow path shown in the drawing the white arrow while, inside temperature was started to increase by energizing the heater 32.

【0024】つぎに、およそ2時間かけて、高温加熱領域の温度を1100〜1300℃に昇温し、この温度を維持しつつ48時間、連続運転した後、室温まで冷却した。 Next, over a period of approximately 2 hours, the temperature of the high temperature heating region heated to 1100 to 1300 ° C., 48 hours while maintaining the temperature, after continuous operation, was cooled to room temperature. そして、焼結体4を管状炉31中から取り出したところ、その高温加熱領域に向き合っていた円盤の盤面上に、厚みおよそ12mmの、透明な層が形成されているのが確認された。 Then, was removed sintered 4 from a tubular furnace 31, the on board of the disk that was facing the high temperature heating region, the thickness of approximately 12 mm, that the transparent layer is formed was confirmed.

【0025】そこでこの透明な層を分析したところ、その厚み方向にc軸が配向した、結晶軸配向性を有する多結晶の酸化亜鉛であることが確認された。 [0025] Therefore Analysis of this transparent layer, the c-axis in the thickness direction is oriented, it was confirmed that the zinc oxide polycrystalline having a crystal axis orientation. (酸化亜鉛のブロックの製造)上記酸化亜鉛の層を、結晶のa面が受光面11aとなり、かつ結晶のc軸と直交する互いに平行な2面のc面が、一対の電極12、13 A layer of (block the production of zinc oxide) above zinc oxide, the light-receiving surface 11a next to a surface of the crystals, and c-plane of the mutually parallel two surfaces perpendicular to the c axis of the crystal, a pair of electrodes 12, 13
が形成される面となるように立方体状に切り出した後、 Was cut into a cube-shaped so that the surface but is formed,
その表面を研磨して、縦5mm×横5mm×高さ5mm And polishing the surface, vertical 5mm × horizontal 5mm × 5mm height
の立方体状のブロックを製造した。 It was prepared of cubic blocks.

【0026】つぎに、上記酸化亜鉛のブロックを、炭酸リチウム水溶液中に浸漬したのち引上げ、乾燥させて、 Next, the block of the zinc oxide, pulling the glass substrate was immersed in aqueous solution of lithium carbonate, dried,
ブロックの表面に炭酸リチウムを付着させた。 On the surface of the block was deposited lithium carbonate. そしてこのブロックを、空気中で、800℃の温度で500時間、加熱してリチウムを拡散させて、内部まで均質に、 And this block, in air, 500 hours at a temperature of 800 ° C., and heated to diffuse the lithium, homogeneous to the inside,
1GΩcm以上に高抵抗化した。 And high resistance more than 1GΩcm. かかる高抵抗化された酸化亜鉛のブロックの光学的禁止帯幅(E opt )は3. Such high resistance has been optically forbidden band width of the block of zinc oxide (E opt) 3.
0eVを超えるものであった。 0eV was more than.

【0027】(紫外線検出素子の製造) 実施例1 図1に示すように、上記で製造した酸化亜鉛のブロック11の、結晶のc軸と直交する互いに平行な2面のc面に、それぞれIn−Ga合金を塗布して一対の電極1 As shown in Example 1 Figure 1 (Production of UV detection element), the block 11 of zinc oxide prepared above, the c-plane of the mutually parallel two surfaces perpendicular to the c axis of the crystal, respectively In a pair of electrodes by applying a -Ga alloy 1
2、13を形成するとともに、上記ブロック11の、結晶のa面に相当する互いに平行な2面のうち図では上側の面を受光面11aとして、実施例1の紫外線検出素子1を製造した。 To form a 2, 13, of the block 11, the out view of mutually parallel two surfaces corresponding to a surface of the crystal as a light-receiving surface 11a of the upper surface, to produce a UV detection element 1 of Example 1.

【0028】比較例1 実施例1ではその一方を受光面11aとしていた、結晶のa面に相当する互いに平行な2面に、それぞれIn− [0028] Comparative Example 1 In Example 1 the one was the light receiving surface 11a, the mutually parallel two surfaces corresponding to a surface of the crystal, respectively In-
Ga合金を塗布して一対の電極を形成するとともに、実施例1では一対の電極12、13を形成していた、結晶のc軸と直交する互いに平行な2面のc面うちの1面を受光面として、比較例1の紫外線検出素子を製造した。 To form a pair of electrodes by applying a Ga alloy, was to form a pair of electrodes 12 and 13 in the first embodiment, the first surface of the c-plane of the two surfaces parallel to each other perpendicular to the c axis of the crystal as the light receiving surface, to produce a UV detection device of Comparative example 1.

【0029】波長特性試験 上記実施例1、比較例1の紫外線検出素子の一対の電極間に、所定の電圧(10V、100Vまたは1000 The wavelength characteristic Test Example 1, between a pair of electrodes of the ultraviolet detecting device of Comparative Example 1, a predetermined voltage (10V, 100 V or 1000
V)の直流電場を印加しつつ、その受光面に、キセノンランプを光源とするモノクロメータを用いて、波長47 While applying a DC electric field of V), on its light-receiving surface, using a monochromator to a xenon lamp as a light source, wavelength 47
0〜300nmの範囲で波長掃引した光を照射した際に、一対の電極間を流れた電流の電流値(明電流、I Upon irradiation of the light wavelength sweep range of from 0 to 300 nm, the current value of the current flowing between a pair of electrodes (bright current, I
light )と、上記光を照射しないときの電流値(暗電流、I dark )との比I light /I darkを求め、当該比と、照射光の波長(nm)と、そしてその際の光子エネルギー(eV)との関係を記録した。 and light), a current value when not irradiated with the light (dark current, determine the specific I light / I dark and I dark), and the ratio, the wavelength of the irradiated light (nm), and photon energy at that time was recorded the relationship between the (eV).

【0030】実施例1の結果を図3、比較例1の結果を図4にそれぞれ示す。 [0030] The results of Example 1 FIG. 3, shown in FIGS. 4 and results of Comparative Example 1. 図4にみるように、受光面が酸化亜鉛の結晶のc面である比較例1の紫外線検出素子は、 As seen in FIG. 4, the ultraviolet detector of Comparative Example 1 light receiving surface is a c-plane of the crystal of zinc oxide,
波長345nm付近と395nm付近の2個所に、光導電効果の大きなピークが現れており、とくに紫外線の波長域の上限に近い波長395nm付近のピークが大きいことから、かかる比較例1の素子は、可視光にも感度を有することが予想された。 At two positions near the vicinity of a wavelength of 345nm and 395nm, and appeared large peak photoconductive effect, especially since the peak near the wavelength of 395nm close to the upper limit of the wavelength range of ultraviolet light is large, elements such Comparative Example 1, the visible to have a sensitivity to light was expected.

【0031】一方、図3にみるように、受光面が酸化亜鉛の結晶のa面である実施例1の紫外線検出素子は、波長330〜360nm付近と395nm付近の2個所に光導電効果のピークが現れたが、このうち波長395n On the other hand, as seen in FIG. 3, the ultraviolet detector of a first embodiment which is a face of the crystal of the light-receiving surface is zinc oxide, the peak of the photoconductive effect at two positions near the vicinity of a wavelength of 330~360nm and 395nm Although appeared, of which wavelength 395n
m付近のピークは比較例1の場合に比べて著しく小さいため、光導電効果の中心は、比較例1に比べて紫外線側にシフトしていることがわかった。 Since the peak in the vicinity of m is considerably smaller than that of Comparative Example 1, the center of the photoconductive effect was found to be shifted to the UV side as compared with Comparative Example 1. そしてこのことから実施例1の素子は、比較例1の素子に比べてその感度域が紫外線側にシフトしており、紫外線に対してより高感度であることが明らかとなった。 The device of Example 1 Therefore, the sensitivity range has shifted to UV side, it was found to be more sensitive to ultraviolet light than the device of Comparative Example 1.

【0032】また、図4にみるように比較例1の紫外線検出素子は、電極間に印加する電場の電圧を変化させても、光導電効果のピークの位置は変わらず、またその強度(ピークの高さ)もあまり変わらなかったが、図3にみるように実施例1の紫外線検出素子は、電極間に印加する電場の電圧を変化させることにより、光導電効果のピークの位置と、その強度とを大きく変化できることがわかった。 [0032] The ultraviolet detector of Comparative Example 1 as seen in Figure 4, be varied electric field of the voltage applied between the electrodes, the position of the peak of the photoconductive effect does not change, also the intensity (peak the height) did not change much in the ultraviolet detector of embodiment 1 as seen in Figure 3, by changing the electric field of the voltage applied between the electrodes, and the position of the peak of the photoconductive effect, the It was found to be significantly changed and intensity.

【0033】周波数依存性試験I 上記実施例1の紫外線検出素子、および比較として、酸化亜鉛のブロックと同寸法の立方体状の、酸化亜鉛の焼結体を用いた比較例2の紫外線検出素子の一対の電極間に、所定の周波数(0.1kHz、0.5kHzまたは1.0kHz)の電場(実効電圧1V)を印加しつつ、 The frequency dependency tests I ultraviolet detector of the first embodiment, and as a comparison, the block with the same size of the zinc oxide cubic, of Comparative Example 2 using a sintered body of zinc oxide ultraviolet detection element between a pair of electrodes, a predetermined frequency (0.1 kHz, 0.5 kHz or 1.0 kHz) while applying an electric field (effective voltage 1V) of
その受光面に、波長360nmの光を断続的に照射した際のインピーダンス(kΩ)の変化を測定した。 On the light receiving surface to measure a change in impedance (kW) at the time of intermittently irradiating the wavelength 360nm light.

【0034】実施例1の結果を図5、比較例2の結果を図6にそれぞれ示す。 [0034] The results of Example 1 FIG. 5, are shown in FIG. 6 the results of Comparative Example 2. 図6にみるように、酸化亜鉛の焼結体からなる比較例2の紫外線検出素子は、インピーダンス変化が、印加した電場の周波数には依存しないものの、その変化量が小さく、かつ矩形性が悪いことがわかった。 As seen in FIG. 6, the ultraviolet detector of Comparative Example 2 formed of a sintered body of zinc oxide, impedance changes, although the frequency of the applied electric field is independent, small amount of change, and poor rectangularity I understand. これに対し、図5にみるように実施例1の紫外線検出素子は、インピーダンス変化の変化量が大きく、かつ比較例2のものに比べてその矩形性が良好であるが、 In contrast, UV detection element of Example 1 as seen in Figure 5, large variation of the impedance change, and its is rectangular is good as compared with that of Comparative Example 2,
インピーダンス変化が、電極に印加した電場の周波数に依存する、具体的には周波数が高いほど、その矩形性は向上するが変化量が小さくなり、逆に周波数が低いほど、その変化量は大きくなるが矩形性が低下する傾向を示すことが確認された。 Impedance change is dependent on the frequency of the electric field applied to the electrode, the higher the frequency in particular, its rectangularity is but variation is reduced enhancing, the lower the frequency the contrary, the amount of change increases There was confirmed to exhibit a tendency to rectangle is lowered.

【0035】周波数依存性試験II そこでつぎに、実施例1の紫外線検出素子の電極間に印加する電場(実効電圧1V)の周波数を100kHz、 The frequency-dependent test II Therefore, next, 100kHz frequency of the electric field (effective voltage 1V) is applied between the electrodes of the UV detector of Example 1,
536kHz(共振周波数)および542kHz(反共振周波数)に設定して、その受光面に、波長360nm 536kHz is set to (resonance frequency) and 542KHz (antiresonance frequency), on the light receiving surface, wavelength 360nm
の光を断続的に照射した際のインピーダンス(kΩ)の変化を測定した。 The a light change in impedance at the time of intermittent irradiation (kW) was measured.

【0036】結果を図7に示す。 [0036] The results are shown in Figure 7. なお図7においては、 In FIG. 7,
各インピーダンス変化の波形をより明確に示すために、 To illustrate waveforms of impedance change more clearly,
各波形の基準レベルを調整して、それぞれの波形をずらして表示している。 And adjusting the reference level of each waveform, it is displayed by shifting the respective waveforms. 図7にみるようにインピーダンス変化は、やはり先の場合と同様に、電極に印加した電場の周波数に依存するが、反共振周波数(この場合は542 Impedance change as seen in Figure 7, again as in the case of earlier, depending on the frequency of the electric field applied to the electrode, the anti-resonance frequency (in this case 542
kHz)の電場を印加したときには、インピーダンス変化を、良好な矩形性を維持しつつ、変化量も十分に大きい状態にできることが確認された。 When applying an electric field of kHz), the impedance changes, while maintaining good rectangularity, variation also it was confirmed that the sufficiently large.

【0037】 [0037]

【発明の効果】以上、詳述したようにこの発明によれば、酸化亜鉛の結晶のa面を受光面とすることによって、紫外線感受材料として酸化亜鉛を使用して、なおかつ従来に比べて紫外線に対する感度が高い紫外線検出素子と、それを用いた紫外線検出方法とを提供できるという特有の作用効果を奏する。 Effect of the Invention] According to the present invention as described in detail, by the light receiving surface of a face of the crystal of the zinc oxide, by using zinc oxide as an ultraviolet sensitive material, and yet compared with the conventional ultraviolet exhibits an ultraviolet detector element sensitive, a unique effect that can be provided an ultraviolet detection method using the same for.

【図面の簡単な説明】 BRIEF DESCRIPTION OF THE DRAWINGS

【図1】この発明の紫外線検出素子の、実施の形態の一例を示す斜視図である。 [1] UV detection element of the present invention, is a perspective view showing an example of the embodiment.

【図2】上記紫外線検出素子に用いる、結晶軸配向性を有する多結晶の酸化亜鉛の製造方法を説明する図である。 [2] used in the ultraviolet detecting device is a diagram for explaining a method of manufacturing a zinc oxide polycrystalline having a crystal axis orientation.

【図3】この発明の実施例1の紫外線検出素子における、明電流と暗電流との比I ligh t /I darkと、照射光の波長と、そのときの光子エネルギーと、そして素子に印加する電場の電圧との関係を示すグラフである。 [3] in the ultraviolet detector of the first embodiment of the present invention, the ratio I ligh t / I dark to the bright current and dark current, and the wavelength of the irradiated light, and the photon energy of the time, and applied to the device is a graph showing the relationship between the voltage of the electric field.

【図4】比較例1の紫外線検出素子における、図3と同様の各特性の関係を示すグラフである。 In the ultraviolet detector of Figure 4 Comparative Example 1 is a graph showing the relationship between the same respective properties as in FIG.

【図5】前記実施例1の紫外線検出素子における、インピーダンス変化と電場の周波数との関係を示すグラフである。 [5] in the ultraviolet detector of Example 1 is a graph showing the relationship between the frequency of the impedance change and the electric field.

【図6】比較例2の紫外線検出素子における、図5と同様の各特性の関係を示すグラフである。 In the ultraviolet detector of Figure 6 Comparative Example 2 is a graph showing the relationship between the same respective properties as Fig.

【図7】実施例1の紫外線検出素子における、インピーダンス変化と電場の周波数との関係を示す別のグラフである。 In the ultraviolet detector of Figure 7 Example 1 is another graph showing a relationship between a frequency of the impedance change and the electric field.

【符号の説明】 DESCRIPTION OF SYMBOLS

1 紫外線検出素子 11 酸化亜鉛のブロック 11a 受光面(酸化亜鉛の結晶のa面) 12、13 電極 1 (a surface of the zinc oxide crystal) ultraviolet detector element 11 blocks 11a light-receiving surface of the zinc oxide 12 electrodes

Claims (3)

    【特許請求の範囲】 [The claims]
  1. 【請求項1】酸化亜鉛の、紫外線照射による光導電効果を利用した紫外線検出素子であって、単結晶、または結晶軸配向性を有する多結晶の酸化亜鉛の、結晶のa面を受光面としたことを特徴とする紫外線検出素子。 1. A zinc oxide, an ultraviolet detection device which utilizes a photoconductive effect by ultraviolet irradiation, the zinc oxide polycrystalline having a single crystal, or the crystal axis orientation, and the light-receiving surface to a surface of the crystal UV detector element characterized in that it has.
  2. 【請求項2】結晶の圧電軸であるc軸の方向に電場を印加する電極を備えている請求項1記載の紫外線検出素子。 2. A UV sensor according to claim 1, characterized in that an electrode for applying an electric field in the direction of the c-axis is a piezoelectric axis of the crystal.
  3. 【請求項3】請求項2記載の紫外線検出素子の電極に、 To 3. The electrode of the ultraviolet detecting device according to claim 2,
    酸化亜鉛の結晶の、圧電効果における反共振周波数の電場を印加しつつ、当該結晶の、光導電効果に基づくインピーダンスの変化を測定することを特徴とする紫外線検出方法。 Crystal zinc oxide, while applying an electric field of anti-resonance frequency in the piezoelectric effect, of the crystal, ultraviolet detection method characterized by measuring the change in impedance based on the photoconductive effect.
JP34169796A 1996-12-20 1996-12-20 Ultraviolet-ray detecting element and detection of ultraviolet rays, using the same Pending JPH10182290A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006225213A (en) * 2005-02-21 2006-08-31 Tosoh Corp Zinc oxide single crystal, substrate for epitaxial growth obtained from the same, and methods for manufacturing them
JP2006278487A (en) * 2005-03-28 2006-10-12 Iwate Industrial Research Center Ultraviolet sensor element and its manufacturing method
JP2007201393A (en) * 2005-12-26 2007-08-09 Iwate Industrial Research Center Photovoltaic ultraviolet sensor
JP2011009292A (en) * 2009-06-23 2011-01-13 Alps Electric Co Ltd Ultraviolet sensor and method of manufacturing the same
JP2011014710A (en) * 2009-07-02 2011-01-20 Murata Mfg Co Ltd Ultraviolet sensor
US7973379B2 (en) 2005-12-26 2011-07-05 Citizen Holdings Co., Ltd. Photovoltaic ultraviolet sensor
JP2013008998A (en) * 2012-09-10 2013-01-10 Iwate Univ Ultraviolet sensor element and manufacturing method thereof

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006225213A (en) * 2005-02-21 2006-08-31 Tosoh Corp Zinc oxide single crystal, substrate for epitaxial growth obtained from the same, and methods for manufacturing them
JP4677796B2 (en) * 2005-02-21 2011-04-27 東ソー株式会社 Method for producing a zinc oxide single crystal
JP2006278487A (en) * 2005-03-28 2006-10-12 Iwate Industrial Research Center Ultraviolet sensor element and its manufacturing method
JP2007201393A (en) * 2005-12-26 2007-08-09 Iwate Industrial Research Center Photovoltaic ultraviolet sensor
US7973379B2 (en) 2005-12-26 2011-07-05 Citizen Holdings Co., Ltd. Photovoltaic ultraviolet sensor
JP2011009292A (en) * 2009-06-23 2011-01-13 Alps Electric Co Ltd Ultraviolet sensor and method of manufacturing the same
JP2011014710A (en) * 2009-07-02 2011-01-20 Murata Mfg Co Ltd Ultraviolet sensor
JP2013008998A (en) * 2012-09-10 2013-01-10 Iwate Univ Ultraviolet sensor element and manufacturing method thereof

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