JP2017101288A - Semiconductor photoelectrode - Google Patents
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Abstract
Description
本発明は、光照射により酸化ターゲット物質または還元ターゲット物質の化学反応を引き起こす光触媒機能を有する半導体光電極に関する。 The present invention relates to a semiconductor photoelectrode having a photocatalytic function that causes a chemical reaction of an oxidation target material or a reduction target material by light irradiation.
光照射により触媒機能を発揮して酸化ターゲット物質または還元ターゲット物質の化学反応を引き起こす光触媒が知られている。例えば、太陽光を利用して、二酸化炭素の発生を伴うことなく水から水素を生成することが可能な光触媒が注目されており、近年盛んに研究されている。 A photocatalyst that exhibits a catalytic function by light irradiation to cause a chemical reaction of an oxidation target substance or a reduction target substance is known. For example, photocatalysts that can generate hydrogen from water without generating carbon dioxide using sunlight have attracted attention and have been actively studied in recent years.
このような光触媒において、光触媒反応の量子収率を向上させるには、光触媒内で光励起した電子・正孔対の空間分離と、反応中間体あるいは生成物が元の物質に戻る逆反応の抑制とが重要となる。逆反応の抑制は、酸化あるいは還元反応を促進するサイト（酸化反応サイトあるいは還元反応サイト）へ、正孔あるいは電子を移動させればよい。例えば、逆反応を効率的に抑制する技術として、酸化反応および還元反応の両方のサイトの配置を制御する電極式の方法が提案されている（非特許文献１，非特許文献２参照）。 In such a photocatalyst, in order to improve the quantum yield of the photocatalytic reaction, spatial separation of electron-hole pairs photoexcited in the photocatalyst and suppression of the reverse reaction in which the reaction intermediate or product returns to the original substance are performed. Is important. In order to suppress the reverse reaction, holes or electrons may be moved to a site (oxidation reaction site or reduction reaction site) that promotes the oxidation or reduction reaction. For example, as a technique for efficiently suppressing the reverse reaction, an electrode-type method for controlling the arrangement of both the oxidation reaction and the reduction reaction has been proposed (see Non-Patent Document 1 and Non-Patent Document 2).
この技術では、二酸化炭素の還元反応の効率を向上させるために、二酸化炭素の還元反応サイトを金属の陽極板とし、水の酸化反応サイトを光触媒機能を有する半導体薄膜電極による陰極板とし、これらを分離して設け、陰極板から陽極板に電子が流れるように電気的な接続をしている。さらには、陽極板と陰極板を電解液に浸漬し、各極をイオン交換膜で分離することで、逆反応の抑制を可能にしている。しかし、このような窒化ガリウム系半導体薄膜電極は、光照射により自己酸化を起こし劣化するため、安定した光電流が得られないことが問題とされている。 In this technology, in order to improve the efficiency of the carbon dioxide reduction reaction, the carbon dioxide reduction reaction site is used as a metal anode plate, and the water oxidation reaction site is used as a cathode plate by a semiconductor thin film electrode having a photocatalytic function. They are provided separately and are electrically connected so that electrons flow from the cathode plate to the anode plate. Furthermore, the reverse reaction can be suppressed by immersing the anode plate and the cathode plate in an electrolyte and separating each electrode with an ion exchange membrane. However, such a gallium nitride based semiconductor thin film electrode is deteriorated due to self-oxidation caused by light irradiation, so that a stable photocurrent cannot be obtained.
上述した自己酸化の防止のために、窒化ガリウム系半導体光電極の表面に酸化ニッケルを助触媒として担持させる技術が提案されている（非特許文献３参照）。この技術では、光照射により半導体光電極上で生じた正孔を、酸化ニッケルによる助触媒で収集することにより自己酸化を抑制している。 In order to prevent the above-mentioned self-oxidation, a technique has been proposed in which nickel oxide is supported as a promoter on the surface of a gallium nitride based semiconductor photoelectrode (see Non-Patent Document 3). In this technique, holes generated on the semiconductor photoelectrode by light irradiation are collected with a promoter made of nickel oxide to suppress autooxidation.
しかしながら、上述した自己酸化抑制の技術では、酸化ニッケルを担持している部分以外は、半導体光電極の表面が露出しているため、自己酸化などの劣化を完全に抑制することは困難であった。 However, since the surface of the semiconductor photoelectrode is exposed except for the portion supporting nickel oxide, it is difficult to completely suppress degradation such as self-oxidation in the above-described self-oxidation suppression technology. .
本発明は、以上のような問題点を解消するためになされたものであり、半導体光電極の劣化を防止した状態で効率的に光触媒反応が得られるようにすることを目的とする。 The present invention has been made to solve the above-described problems, and an object thereof is to efficiently obtain a photocatalytic reaction in a state in which deterioration of a semiconductor photoelectrode is prevented.
本発明に係る半導体光電極は、ＩＩＩ−Ｖ族化合物半導体からなる第１半導体層と、対象とする物質の反応を起こさせる第１半導体層の反応領域を被覆して形成された酸化物半導体からなる第２半導体層とを備える。 The semiconductor photoelectrode according to the present invention includes a first semiconductor layer made of a III-V group compound semiconductor and an oxide semiconductor formed so as to cover a reaction region of the first semiconductor layer that causes a reaction of a target substance. And a second semiconductor layer.
上記半導体光電極において、第１半導体層に対して助触媒機能を有する材料からなる複数の島部が第２半導体層の反応領域に分散配置されて形成された助触媒層を備えるようにしてもよい。この材料は、Ｐｔ、Ｐｄ、Ｃｏ、Ａｕ、Ａｇ、Ｒｕ、Ｃｕ、Ｃｒ、Ａｌ、Ｆｅ、Ｉｎ、Ｎｉ、Ｒｈ、Ｒｅ、または、これらの金属の合金、または、これら金属の酸化物のいずれかから構成されていればよい。 In the semiconductor photoelectrode, a plurality of island portions made of a material having a cocatalyst function with respect to the first semiconductor layer may be provided with a cocatalyst layer formed in a dispersed manner in the reaction region of the second semiconductor layer. Good. This material is either Pt, Pd, Co, Au, Ag, Ru, Cu, Cr, Al, Fe, In, Ni, Rh, Re, or an alloy of these metals, or an oxide of these metals. It should just be comprised from.
以上説明したことにより、本発明によれば、半導体光電極の劣化を防止した状態で効率的に光触媒反応が得られるになる。 As described above, according to the present invention, a photocatalytic reaction can be efficiently obtained in a state where deterioration of the semiconductor photoelectrode is prevented.
以下、本発明の実施の形態について図を参照して説明する。図１は、本発明の実施の形態における半導体光電極の一部構成を示す断面図である。この半導体光電極は、ＩＩＩ−Ｖ族化合物半導体からなる第１半導体層１０１と、酸化物半導体からなる第２半導体層１０２とを備える。第２半導体層１０２は、対象とする物質の反応を起こさせる第１半導体層１０１の反応領域を被覆して膜状に形成されている。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a partial configuration of a semiconductor photoelectrode according to an embodiment of the present invention. This semiconductor photoelectrode includes a first semiconductor layer 101 made of a III-V group compound semiconductor and a second semiconductor layer 102 made of an oxide semiconductor. The second semiconductor layer 102 is formed in a film shape so as to cover a reaction region of the first semiconductor layer 101 that causes a reaction of a target substance.
例えば、図２に示すように、サファイアからなる基板１１１の上に、第１半導体層１０１を形成し、反応領域１２１における第１半導体層１０１の表面を第２半導体層１０２で覆えばよい。また、第１半導体層１０１には、配線１１２を電気的に接続する。配線１１２は、銅配線、銀配線、金配線などの金属配線であればよい。 For example, as shown in FIG. 2, the first semiconductor layer 101 may be formed on a substrate 111 made of sapphire, and the surface of the first semiconductor layer 101 in the reaction region 121 may be covered with the second semiconductor layer 102. Further, the wiring 112 is electrically connected to the first semiconductor layer 101. The wiring 112 may be a metal wiring such as a copper wiring, a silver wiring, or a gold wiring.
第１半導体層１０１は、光触媒機能を有する窒化ガリウム（ＧａＮ）、窒化アルミニウムガリウム（ＡｌＧａＮ）、窒化インジウムガリウム（ＩｎＧａＮ）、窒化アルミニウムガリウム（ＡｌＧａＮ）、リン化インジウム（ＩｎＰ）、リン化インジウムガリウム（ＩｎＧａＰ）、ヒ化ガリウム（ＧａＡｓ）などのＩＩＩ−Ｖ族化合物半導体から構成すればよい。また、例えば、ＧａＮ層とＡｌＧａＮ層との積層構造から第１半導体層１０１を構成してもよい。 The first semiconductor layer 101 has a photocatalytic function of gallium nitride (GaN), aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), indium phosphide (InP), indium gallium phosphide ( What is necessary is just to comprise from III-V group compound semiconductors, such as InGaP) and gallium arsenide (GaAs). Further, for example, the first semiconductor layer 101 may be configured from a stacked structure of a GaN layer and an AlGaN layer.
第２半導体層１０２は、酸化亜鉛（ＺｎＯ）、酸化チタン（ＴｉＯ2）、酸化鉄（Ｆｅ2Ｏ3）、酸化タングステン（ＷＯ3）、酸化ニオブ（Ｎｂ2Ｏ3）などの酸化物半導体から構成すればよい。なお、第２半導体層１０２は、伝導帯端および荷電子帯端のエネルギーが第１半導体層１０１より低く、伝導帯端のエネルギーは、第１半導体層１０１の荷電子帯端のエネルギーより高い状態となっていればよい。 The second semiconductor layer 102 is made of an oxide semiconductor such as zinc oxide (ZnO), titanium oxide (TiO 2 ), iron oxide (Fe 2 O 3 ), tungsten oxide (WO 3 ), niobium oxide (Nb 2 O 3 ). What is necessary is just to comprise. In the second semiconductor layer 102, the energy at the conduction band edge and the valence band edge is lower than that at the first semiconductor layer 101, and the energy at the conduction band edge is higher than the energy at the valence band edge of the first semiconductor layer 101. It only has to be.
また、第１半導体層１０１の伝導帯端のエネルギーは、水の還元電位より高く、第２半導体層１０２の荷電子帯端のエネルギーは、水の酸化電位より低ければよい。この構成とすることで、実施の形態における半導体光電極を用いることで、光触媒反応により水の電気分解が可能となる。ターゲット物質の酸化電位、還元電位に対応させて上記材料構成を適宜に設定すればよい。 Further, the energy at the conduction band edge of the first semiconductor layer 101 should be higher than the reduction potential of water, and the energy at the valence band edge of the second semiconductor layer 102 should be lower than the oxidation potential of water. With this configuration, by using the semiconductor photoelectrode in the embodiment, water can be electrolyzed by a photocatalytic reaction. The material structure may be set as appropriate in accordance with the oxidation potential and reduction potential of the target substance.
ここで、第１半導体層１０１をｎ型とすれば、実施の形態における半導体光電極は、酸化反応サイトとなる。第１半導体層１０１をＧａＮ層とＡｌＧａＮ層との積層構造とした場合、第２半導体層１０２の側のＧａＮ層を、ｎ型とすればよい。よく知られているように、Ｓｉをドープすることで、ＧａＮはｎ型となる。一方、第１半導体層１０１をｐ型とすれば、実施の形態における半導体光電極は、還元反応サイトとなる。 Here, if the first semiconductor layer 101 is n-type, the semiconductor photoelectrode in the embodiment becomes an oxidation reaction site. When the first semiconductor layer 101 has a stacked structure of a GaN layer and an AlGaN layer, the GaN layer on the second semiconductor layer 102 side may be n-type. As is well known, GaN becomes n-type by doping Si. On the other hand, if the first semiconductor layer 101 is p-type, the semiconductor photoelectrode in the embodiment becomes a reduction reaction site.
ところで、図３に示すように、第２半導体層１０２の上に、第１半導体層に対して助触媒機能を有する材料からなる複数の島部が分散配置されて形成された助触媒層１０３を備えるようにしてもよい。助触媒層１０３は、第１半導体層１０１が配置されている側とは反対の、第２半導体層１０２上の反応領域に設けられていればよい。助触媒層１０３の各島部の間には、第２半導体層１０２の表面が露出している。助触媒層１０３を構成する助触媒は、Ｐｔ、Ｐｄ、Ｃｏ、Ａｕ、Ａｇ、Ｒｕ、Ｃｕ、Ｃｒ、Ａｌ、Ｆｅ、Ｉｎ、Ｎｉ、Ｒｈ、Ｒｅ、または、これらの金属の合金、または、これら金属の酸化物のいずれかから構成されていればよい。 By the way, as shown in FIG. 3, the promoter layer 103 formed by dispersing and arranging a plurality of island parts made of a material having a promoter function with respect to the first semiconductor layer is formed on the second semiconductor layer 102. You may make it prepare. The promoter layer 103 may be provided in the reaction region on the second semiconductor layer 102 opposite to the side on which the first semiconductor layer 101 is disposed. The surface of the second semiconductor layer 102 is exposed between the island portions of the promoter layer 103. The promoter constituting the promoter layer 103 is Pt, Pd, Co, Au, Ag, Ru, Cu, Cr, Al, Fe, In, Ni, Rh, Re, or an alloy of these metals, or these What is necessary is just to be comprised from either of the metal oxides.
ところで、実施の形態における半導体光電極は、水などの媒質中に配置（浸漬）して用いればよい。例えば、図４に示すように、ガラスなどの透光性を有する部材から構成された光透過セル２０１に、媒質２０２を収容し、媒質２０２中に半導体光電極１００を浸漬して配置する。光透過セル２０１は、例えば、内径２０ｍｍ，内容量３０ｍＬの試験管から構成することができる。また、媒質２０２中には、例えば白金からなる対極２０３も浸漬して配置する。対極２０３は、例えば、Ｐｔ線［ＢＡＳ製，Ｐｔ電極（型番００２２２２）］であればよい。第１半導体層１０１をｎ型とした場合、対極２０３は、還元反応サイトとなる。一方、第１半導体層１０１をｐ型とした場合、対極２０３は、酸化反応サイトとなる。 By the way, the semiconductor photoelectrode in the embodiment may be disposed (immersed) in a medium such as water. For example, as shown in FIG. 4, a medium 202 is accommodated in a light transmission cell 201 formed of a light-transmitting member such as glass, and the semiconductor photoelectrode 100 is immersed in the medium 202 and disposed. The light transmission cell 201 can be composed of, for example, a test tube having an inner diameter of 20 mm and an inner volume of 30 mL. Further, a counter electrode 203 made of, for example, platinum is also immersed in the medium 202. The counter electrode 203 may be, for example, a Pt line [manufactured by BAS, Pt electrode (model number 002222)]. When the first semiconductor layer 101 is n-type, the counter electrode 203 becomes a reduction reaction site. On the other hand, when the first semiconductor layer 101 is p-type, the counter electrode 203 becomes an oxidation reaction site.
また、半導体光電極１００の第１半導体層１０１に接続した配線１１２および対極２０３は、電流計２０４に接続する。また、光透過セル２０１に収容している媒質２０２は、攪拌子２０５を回転させることで攪拌する。また、半導体光電極１００の第２半導体層１０２形成側には、光源２０６からの光を照射する。太陽光を光源としてもよい。 Further, the wiring 112 and the counter electrode 203 connected to the first semiconductor layer 101 of the semiconductor photoelectrode 100 are connected to an ammeter 204. The medium 202 accommodated in the light transmission cell 201 is agitated by rotating the agitator 205. In addition, the light from the light source 206 is irradiated on the side of the semiconductor photoelectrode 100 where the second semiconductor layer 102 is formed. Sunlight may be used as the light source.
媒質２０２は、Ｈ2ＳＯ4，ＨＣｌ、Ｎａ2ＳＯ4、ＫＨＣＯ3のなどの電解質が溶解している水溶液であればよい。上記構成により水が電気分解できる（水の酸化反応による酸素生成、水の酸化により生じたプロトンの還元による水素生成）。また、実施の形態における半導体光電極１００を用いることで、二酸化炭素を還元ターゲット物質とし、一酸化炭素、ギ散、メタノール、メタンの炭化水素類を生成することも可能である。 The medium 202 may be an aqueous solution in which an electrolyte such as H 2 SO 4 , HCl, Na 2 SO 4 , or KHCO 3 is dissolved. Water can be electrolyzed with the above structure (oxygen generation by water oxidation reaction, hydrogen generation by reduction of protons generated by water oxidation). In addition, by using the semiconductor photoelectrode 100 according to the embodiment, carbon monoxide can be used as a reduction target material, and hydrocarbons such as carbon monoxide, Gifusan, methanol, and methane can be generated.
［実施例］
次に、実施例を用いてより詳細に説明する。まず、半導体光電極（試料）の作製について説明する。
[Example]
Next, it demonstrates in detail using an Example. First, production of a semiconductor photoelectrode (sample) will be described.
［試料１］
はじめに、試料１について説明する。まず、主表面を（０００１）面としたサファイアからなる基板１１１を用意し、この上に、シリコンをドープすることでｎ型としたＧａＮを堆積し、引き続いて、アルミニウムの組成比を９．６％としたＡｌＧａＮを堆積して第１半導体層１０１を形成する。例えば、よく知られた有機金属気相成長法によるエピタキシャル成長で、ＧａＮおよびＡｌＧａＮが堆積できる。ＧａＮ層は層厚２ｎｍ、ＡｌＧａＮ層は層厚１０７ｎｍとする。
[Sample 1]
First, the sample 1 will be described. First, a substrate 111 made of sapphire having a main surface of (0001) plane is prepared, and n-type GaN is deposited thereon by doping silicon, and subsequently the composition ratio of aluminum is 9.6. % Of AlGaN is deposited to form the first semiconductor layer 101. For example, GaN and AlGaN can be deposited by epitaxial growth by a well-known metal organic chemical vapor deposition method. The GaN layer has a thickness of 2 nm, and the AlGaN layer has a thickness of 107 nm.
次に、第１半導体層１０１の上に、第２半導体層１０２を形成する。まず、Ｚｎの有機化合物を有機溶剤に溶解した溶液から構成したＭＯＤ（Metal Organic Decomposition）コート剤を用意し、このＭＯＤコート剤を第１半導体層１０１の上に塗布して塗布膜を形成する。ＭＯＤコート剤は、例えば、株式会社 高純度化学研究所製のＺｎ−０５であればよい。Ｚｎ−０５を１０倍に希釈して用いる。塗布は、スピンコート法により、回転数５００ｒｐｍ（時間１０秒）→回転数５０００ｒｐｍ（時間４０秒）の条件で実施すればよい。 Next, the second semiconductor layer 102 is formed on the first semiconductor layer 101. First, a MOD (Metal Organic Decomposition) coating agent composed of a solution in which an organic compound of Zn is dissolved in an organic solvent is prepared, and this MOD coating agent is applied onto the first semiconductor layer 101 to form a coating film. The MOD coating agent may be, for example, Zn-05 manufactured by Kojundo Chemical Laboratory Co., Ltd. Zn-05 is diluted 10 times and used. Application may be performed by a spin coating method under conditions of a rotation speed of 500 rpm (time: 10 seconds) → a rotation speed of 5000 rpm (time: 40 seconds).
次に、塗布膜を焼成してＺｎＯとすることで、第２半導体層１０２を得る。例えば、電気炉を用い、大気雰囲気中で５５０℃で３０分間熱処理することで塗布膜を焼成すればよい。得られた第２半導体層１０２は、厚さ２５ｎｍである。 Next, the second semiconductor layer 102 is obtained by baking the coating film to obtain ZnO. For example, the coating film may be baked by heat treatment at 550 ° C. for 30 minutes in an air atmosphere using an electric furnace. The obtained second semiconductor layer 102 has a thickness of 25 nm.
次に、上述したことにより作製した積層膜を切断することで半導体光電極チップを形成した。チップサイズは、平面視１０ｍｍ×１５ｍｍとした。また、形成した半導体光電極チップの一部表面（第２半導体層１０２）をダイヤモンドスクライバーを用いて剥離し、一部の第１半導体層１０１を露出させる。このようにして露出させた一部の第１半導体層１０１表面に、Ｉｎをロウ材として配線１１２をロウ付けし、試料１とした。なお、Ｉｎからなるロウ付け部は、エポキシ樹脂で被覆した。一部の第１半導体層１０１が露出したロウ付け領域以外の１０ｍｍ×１０ｍｍの領域が、反応領域となる。 Next, a semiconductor photoelectrode chip was formed by cutting the laminated film prepared as described above. The chip size was 10 mm × 15 mm in plan view. Further, a part of the surface (second semiconductor layer 102) of the formed semiconductor photoelectrode chip is peeled off using a diamond scriber to expose a part of the first semiconductor layer 101. A wiring 1 was brazed with In as a brazing material on the surface of a part of the first semiconductor layer 101 exposed in this manner, thereby obtaining a sample 1. The brazing portion made of In was covered with an epoxy resin. A region of 10 mm × 10 mm other than the brazing region where a part of the first semiconductor layer 101 is exposed serves as a reaction region.
［試料２］
次に、試料２について説明する。試料２は、試料１の構成に加え、酸化ニッケルからなる助触媒層を設けた。まず、試料１と同様にして基板１１１の上にＧａＮ層およびＡｌＧａＮ層からなる第１半導体層１０１を形成し、第１半導体層１０１の上に第２半導体層１０２を形成する。
[Sample 2]
Next, the sample 2 will be described. Sample 2 was provided with a promoter layer made of nickel oxide in addition to the configuration of sample 1. First, in the same manner as in the sample 1, the first semiconductor layer 101 including the GaN layer and the AlGaN layer is formed on the substrate 111, and the second semiconductor layer 102 is formed on the first semiconductor layer 101.
次に、第２半導体層１０２の上に、助触媒層１０３を形成する。まず、Ｎｉの有機化合物を有機溶剤に溶解した溶液から構成したＭＯＤコート剤を用意し、このＭＯＤコート剤を２００倍に希釈し、この希釈剤を第２半導体層１０２の上に塗布して塗布膜を形成する。ＭＯＤコート剤は、例えば、株式会社 高純度化学研究所製のＮｉ−０３であればよい。塗布は、スピンコート法により、回転数５００ｒｐｍ（時間１０秒）→回転数５０００ｒｐｍ（時間４０秒）の条件で実施すればよい。 Next, the promoter layer 103 is formed on the second semiconductor layer 102. First, a MOD coating agent composed of a solution in which an organic compound of Ni is dissolved in an organic solvent is prepared, the MOD coating agent is diluted 200 times, and this diluent is applied onto the second semiconductor layer 102 and applied. A film is formed. The MOD coating agent may be, for example, Ni-03 manufactured by Kojundo Chemical Laboratory Co., Ltd. Application may be performed by a spin coating method under conditions of a rotation speed of 500 rpm (time: 10 seconds) → a rotation speed of 5000 rpm (time: 40 seconds).
次に、塗布膜を焼成してＮｉＯとすることで、助触媒層１０３を得る。例えば、電気炉を用い、大気雰囲気中で６００℃で３０分間熱処理することで塗布膜を焼成すればよい。得られた助触媒層１０３を走査型電子顕微鏡で観察したところ、厚さ数μｍ、平面視の径が５〜２０μｍの複数の島部から構成されていることが確認できた。次に、上述したことにより作製した積層膜を試料１と同様にしてチップとすることで、試料２とした。 Next, the co-catalyst layer 103 is obtained by baking the coating film to form NiO. For example, the coating film may be baked by heat treatment at 600 ° C. for 30 minutes in an air atmosphere using an electric furnace. When the obtained promoter layer 103 was observed with a scanning electron microscope, it was confirmed that the promoter layer 103 was composed of a plurality of island portions having a thickness of several μm and a diameter in a plan view of 5 to 20 μm. Next, Sample 2 was obtained by using the laminated film manufactured as described above as a chip in the same manner as Sample 1.
［試料３］
次に、試料３について説明する。試料３は、試料１の構成に加え、ニッケルからなる助触媒層を設けた。まず、試料１と同様にして基板１１１の上にＧａＮ層およびＡｌＧａＮ層からなる第１半導体層１０１を形成し、第１半導体層１０１の上に第２半導体層１０２を形成する。
[Sample 3]
Next, the sample 3 will be described. Sample 3 was provided with a promoter layer made of nickel in addition to the configuration of sample 1. First, in the same manner as in the sample 1, the first semiconductor layer 101 including the GaN layer and the AlGaN layer is formed on the substrate 111, and the second semiconductor layer 102 is formed on the first semiconductor layer 101.
次に、第２半導体層１０２の上に、助触媒層１０３を形成する。まず、よく知られたスパッタ法によりＮｉを厚さ５ｎｍ程度に堆積することで、第２半導体層１０２の上に助触媒層１０３を得る。得られた助触媒層１０３を走査型電子顕微鏡で観察したところ、平面視の径が５〜１０μｍの複数の島部から構成されていることが確認できた。次に、上述したことにより作製した積層膜を試料１と同様にしてチップとすることで、試料３とした。 Next, the promoter layer 103 is formed on the second semiconductor layer 102. First, the promoter layer 103 is obtained on the second semiconductor layer 102 by depositing Ni to a thickness of about 5 nm by a well-known sputtering method. When the obtained promoter layer 103 was observed with a scanning electron microscope, it was confirmed that the promoter layer 103 was composed of a plurality of island portions having a diameter in a plan view of 5 to 10 μm. Next, Sample 3 was obtained by using the laminated film prepared as described above as a chip in the same manner as Sample 1.
［比較試料１］
次に、比較試料１について説明する。比較試料１では、第２半導体層１０２を用いずに、第１半導体層１０１のみで構成した。まず、試料１と同様にして基板１１１の上にＧａＮ層およびＡｌＧａＮ層からなる第１半導体層１０１を形成する。次に、第１半導体層１０１が形成された基板１１１を切断することで半導体光電極チップを形成した。チップサイズは、平面視１０ｍｍ×１５ｍｍとした。また、一部の第１半導体層１０１の表面に、Ｉｎをロウ材として配線１１２をロウ付けし、比較試料１とした。なお、Ｉｎからなるロウ部は、エポキシ樹脂で被覆した。第１半導体層１０１におけるロウ付け領域以外の１０ｍｍ×１０ｍｍの領域が、反応領域となる。
[Comparative sample 1]
Next, the comparative sample 1 will be described. In the comparative sample 1, the second semiconductor layer 102 was not used, and only the first semiconductor layer 101 was used. First, the first semiconductor layer 101 composed of a GaN layer and an AlGaN layer is formed on the substrate 111 in the same manner as the sample 1. Next, a semiconductor photoelectrode chip was formed by cutting the substrate 111 on which the first semiconductor layer 101 was formed. The chip size was 10 mm × 15 mm in plan view. In addition, a wiring 112 was brazed with In as a brazing material on a part of the surface of the first semiconductor layer 101 to obtain a comparative sample 1. The brazing part made of In was covered with an epoxy resin. A region of 10 mm × 10 mm other than the brazing region in the first semiconductor layer 101 is a reaction region.
［比較試料２］
次に、比較試料２について説明する。比較試料２では、比較試料１の構成に加え、第１半導体層１０１の上に酸化ニッケルからなる助触媒層を設けた。まず、比較試料１と同様にして基板１１１の上にＧａＮ層およびＡｌＧａＮ層からなる第１半導体層１０１を形成する。次に、試料２と同様にすることで、第１半導体層１０１の上に、酸化ニッケルからなる助触媒層を形成する。
[Comparative sample 2]
Next, the comparative sample 2 will be described. In Comparative Sample 2, a promoter layer made of nickel oxide was provided on the first semiconductor layer 101 in addition to the configuration of Comparative Sample 1. First, the first semiconductor layer 101 composed of a GaN layer and an AlGaN layer is formed on the substrate 111 in the same manner as the comparative sample 1. Next, a promoter layer made of nickel oxide is formed on the first semiconductor layer 101 in the same manner as the sample 2.
次に、第１半導体層１０１が形成された基板１１１を切断することで半導体光電極チップを形成した。チップサイズは、平面視１０ｍｍ×１５ｍｍとした。また、比較試料１と同様に、酸化ニッケルからなる助触媒層が形成されている一部の第１半導体層１０１の表面に、Ｉｎをロウ材として配線１１２をロウ付けし、比較試料２とした。 Next, a semiconductor photoelectrode chip was formed by cutting the substrate 111 on which the first semiconductor layer 101 was formed. The chip size was 10 mm × 15 mm in plan view. Similarly to the comparative sample 1, the wiring 112 was brazed with In as a brazing material on the surface of a part of the first semiconductor layer 101 on which the promoter layer made of nickel oxide was formed, thereby obtaining a comparative sample 2. .
［比較試料３］
次に、比較試料３について説明する。比較試料３では、比較試料１の構成に加え、第１半導体層１０１の上にニッケルからなる助触媒層を設けた。まず、比較試料１と同様にして基板１１１の上にＧａＮ層およびＡｌＧａＮ層からなる第１半導体層１０１を形成する。次に、試料３と同様にすることで、第１半導体層１０１の上に、ニッケルからなる助触媒層を形成する。
[Comparative sample 3]
Next, the comparative sample 3 will be described. In Comparative Sample 3, in addition to the configuration of Comparative Sample 1, a promoter layer made of nickel was provided on the first semiconductor layer 101. First, the first semiconductor layer 101 composed of a GaN layer and an AlGaN layer is formed on the substrate 111 in the same manner as the comparative sample 1. Next, a promoter layer made of nickel is formed on the first semiconductor layer 101 in the same manner as the sample 3.
次に、第１半導体層１０１が形成された基板１１１を切断することで半導体光電極チップを形成した。チップサイズは、平面視１０ｍｍ×１５ｍｍとした。また、比較試料１と同様に、酸化ニッケルからなる助触媒層が形成されている一部の第１半導体層１０１の表面に、Ｉｎをロウ材として配線１１２をロウ付けし、比較試料３とした。 Next, a semiconductor photoelectrode chip was formed by cutting the substrate 111 on which the first semiconductor layer 101 was formed. The chip size was 10 mm × 15 mm in plan view. Similarly to the comparative sample 1, the wiring 112 is brazed with In as a brazing material on the surface of a part of the first semiconductor layer 101 on which the promoter layer made of nickel oxide is formed, thereby obtaining a comparative sample 3. .
［酸化還元反応試験］
次に、試料１，試料２，試料３，比較試料１，比較試料２，比較試料３を用いた酸化還元反応試験の結果について説明する。この試験では、図４を用いて説明したセルを用い、媒質２０２として濃度１Ｍの水酸化ナトリウム水溶液（２０ｍＬ）を用いた。半導体光電極１００として試料１，試料２，試料３，比較試料１，比較試料２，比較試料３を用いた。
[Redox reaction test]
Next, the result of the oxidation-reduction reaction test using Sample 1, Sample 2, Sample 3, Comparative Sample 1, Comparative Sample 2, and Comparative Sample 3 will be described. In this test, the cell described with reference to FIG. 4 was used, and a 1 M sodium hydroxide aqueous solution (20 mL) was used as the medium 202. As the semiconductor photoelectrode 100, Sample 1, Sample 2, Sample 3, Comparative Sample 1, Comparative Sample 2, and Comparative Sample 3 were used.
試験においては、媒質２０２にアルゴンガスを２００ｍＬ／ｍｉｎで３０分間バブリングして脱泡・置換した後、光透過セル２０１を、シリコーンとフッ素樹脂との２層構造のセプタムで密閉した。セル内の圧力は大気圧とした。また、光源２０６として、３００Ｗの高圧キセノンランプ（３６０ｎｍ以上をカット、照度８ｍＷ／ｃｍ2）を用いた。光源２０６からの光は、セルの光透過セル２０１の外側から、半導体光電極１００の反応領域に均一に照射した。また、媒質２０２の攪拌は、光透過セル２０１の底部中心に配置した攪拌子２０５を、図示しないスターらを用いて２５０ｒｐｍの回転速度で回転させて実施した。 In the test, argon gas was bubbled through the medium 202 at 200 mL / min for 30 minutes for defoaming and substitution, and then the light transmission cell 201 was sealed with a two-layered septum of silicone and fluororesin. The pressure in the cell was atmospheric pressure. Further, as the light source 206, a 300 W high-pressure xenon lamp (360 nm or more cut, illuminance 8 mW / cm 2 ) was used. The light from the light source 206 was uniformly applied to the reaction region of the semiconductor photoelectrode 100 from the outside of the light transmission cell 201 of the cell. Further, the stirring of the medium 202 was performed by rotating the stirring bar 205 arranged at the center of the bottom of the light transmission cell 201 at a rotational speed of 250 rpm using a star (not shown).
光照射中に電流計２０４で測定される光電流量を記録した。記録した結果を図５示す。図５には、試料１の結果を黒ひし形で示し、比較試料１の結果を白ひし形で示す。また、任意の時間が経過した時点で、光透過セル２０１内のガスをセプタム部分からシリンジで採取し、ガスクロマトグラフ質量分析計にて反応生成物を分析した。この分析では、水素と酸素が生成していることが確認された。 The photoelectric flow rate measured by the ammeter 204 during light irradiation was recorded. The recorded results are shown in FIG. In FIG. 5, the result of the sample 1 is shown by a black rhombus, and the result of the comparative sample 1 is shown by a white rhombus. Moreover, when arbitrary time passed, the gas in the light transmission cell 201 was extract | collected with the syringe from the septum part, and the reaction product was analyzed with the gas chromatograph mass spectrometer. This analysis confirmed the generation of hydrogen and oxygen.
図５に示すように、試料１では、１００時間光照射後も安定した電流が維持された。これに対し、比較例１では、光照射１３時間で電流量が０になった。これは、ｎ−ＧａＮ／ＡｌＧａＮによる第１半導体層１０１の光エッチングが進行したことが、原因と考えられる。 As shown in FIG. 5, in Sample 1, a stable current was maintained even after 100 hours of light irradiation. On the other hand, in Comparative Example 1, the amount of current became 0 after 13 hours of light irradiation. This is considered to be caused by the progress of photoetching of the first semiconductor layer 101 by n-GaN / AlGaN.
次に、試料１，試料２，試料３，比較試料１，比較試料２，比較試料３の各々おける、水素ガス生成量、酸素ガス生成量、安定した光電流の寿命を、以下の表１に示す。 Next, the hydrogen gas generation amount, oxygen gas generation amount, and stable photocurrent lifetime in each of Sample 1, Sample 2, Sample 3, Comparative Sample 1, Comparative Sample 2, and Comparative Sample 3 are shown in Table 1 below. Show.
ＺｎＯからなる第２半導体層の表面に助触媒ＮｉＯまたはＮｉを分散した助触媒層を形成した試料２および試料３においても、１００時間以上安定した電流が維持された。さらに、助触媒層を形成していない試料１の場合よりも、試料２および試料３の水素生成量はそれぞれ約２倍および７倍に向上した。この結果は、光照射により第１半導体層の表面に得られた正孔が、効率よく助触媒に収集されることで、再結合が抑制されたことを示している。助触媒層は、第２半導体層の表面にｎｍオーダーの微細な粒子（島部）として緻密に分散しているため、より電荷分離が促進されたと考えられる。 Also in Sample 2 and Sample 3 in which the promoter NiO or the promoter layer in which Ni was dispersed was formed on the surface of the second semiconductor layer made of ZnO, a stable current was maintained for 100 hours or more. Furthermore, the hydrogen production amounts of Sample 2 and Sample 3 were improved by about 2 times and 7 times, respectively, as compared with Sample 1 in which no promoter layer was formed. This result indicates that the recombination is suppressed by efficiently collecting holes obtained on the surface of the first semiconductor layer by light irradiation on the promoter. Since the promoter layer is densely dispersed as fine particles (islands) on the order of nm on the surface of the second semiconductor layer, it is considered that charge separation is further promoted.
次に、従来の電極構造である比較試料２，比較試料３の結果と比較する。比較試料２，比較試料３いずれも、ＮｉＯまたはＮｉ助触媒を分散した助触媒層を設けることで、比較試料１よりも水素生成量は向上した。しかしながら、光電流の寿命はそれぞれ３４時間、２９時間であり、試料１と比較して大幅な向上は確認されなかった。 Next, it compares with the result of the comparative sample 2 and the comparative sample 3 which are the conventional electrode structures. Both Comparative Sample 2 and Comparative Sample 3 were provided with a promoter layer in which NiO or Ni promoter was dispersed, so that the hydrogen generation amount was improved as compared with Comparative Sample 1. However, the lifetime of the photocurrent was 34 hours and 29 hours, respectively, and no significant improvement was confirmed as compared with Sample 1.
以上の結果から、実施の形態における半導体光電極を、光反応による酸化還元反応の酸化電極として用いることで、第１半導体層１０１のエッチングが抑制され、電極寿命が大きく向上することが確認された。 From the above results, it was confirmed that the etching of the first semiconductor layer 101 was suppressed and the electrode life was greatly improved by using the semiconductor photoelectrode in the embodiment as an oxidation electrode for the oxidation-reduction reaction by photoreaction. .
以上に説明したように、本発明によれば、ＩＩＩ−Ｖ族化合物半導体からなる第１半導体層の上に、酸化物半導体からなる第２半導体層を備えるようにしたので、半導体光電極の劣化を防止した状態で効率的に光触媒反応が得られるようなる。 As described above, according to the present invention, since the second semiconductor layer made of an oxide semiconductor is provided on the first semiconductor layer made of a III-V group compound semiconductor, the semiconductor photoelectrode is deteriorated. In this state, the photocatalytic reaction can be efficiently obtained.
なお、本発明は以上に説明した実施の形態に限定されるものではなく、本発明の技術的思想内で、当分野において通常の知識を有する者により、多くの変形および組み合わせが実施可能であることは明白である。 The present invention is not limited to the embodiment described above, and many modifications and combinations can be implemented by those having ordinary knowledge in the art within the technical idea of the present invention. It is obvious.
１０１…第１半導体層、１０２…第２半導体層、１０３…助触媒層、１１１…基板、１１２…配線、１２１…反応領域。 DESCRIPTION OF SYMBOLS 101 ... 1st semiconductor layer, 102 ... 2nd semiconductor layer, 103 ... Cocatalyst layer, 111 ... Substrate, 112 ... Wiring, 121 ... Reaction region.
Claims (3)
対象とする物質の反応を起こさせる前記第１半導体層の反応領域を被覆して形成された酸化物半導体からなる第２半導体層と
を備えることを特徴とする半導体光電極。 A first semiconductor layer made of a III-V group compound semiconductor;
A semiconductor photoelectrode, comprising: a second semiconductor layer made of an oxide semiconductor formed to cover a reaction region of the first semiconductor layer that causes a reaction of a target substance.
前記第１半導体層に対して助触媒機能を有する材料からなる複数の島部が前記第２半導体層の前記反応領域に分散配置されて形成された助触媒層
を備えることを特徴とする半導体光電極。 The semiconductor photoelectrode according to claim 1, wherein
A semiconductor light comprising: a promoter layer formed by dispersing and arranging a plurality of island parts made of a material having a promoter function with respect to the first semiconductor layer in the reaction region of the second semiconductor layer electrode.
前記材料は、Ｐｔ、Ｐｄ、Ｃｏ、Ａｕ、Ａｇ、Ｒｕ、Ｃｕ、Ｃｒ、Ａｌ、Ｆｅ、Ｉｎ、Ｎｉ、Ｒｈ、Ｒｅ、または、これらの金属の合金、または、これら金属の酸化物のいずれかから構成されている
ことを特徴とする半導体光電極。 The semiconductor photoelectrode according to claim 2, wherein
The material is Pt, Pd, Co, Au, Ag, Ru, Cu, Cr, Al, Fe, In, Ni, Rh, Re, or an alloy of these metals, or an oxide of these metals. A semiconductor photoelectrode comprising:
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2019107627A (en) * | 2017-12-20 | 2019-07-04 | 日本電信電話株式会社 | Semiconductor photoelectrode |
| WO2020153080A1 (en) * | 2019-01-25 | 2020-07-30 | シャープ株式会社 | Photocatalytic sheet |
| WO2023089654A1 (en) * | 2021-11-16 | 2023-05-25 | 日本電信電話株式会社 | Production method for semiconductor photoelectrode |
| JP2023117608A (en) * | 2022-02-14 | 2023-08-24 | 本田技研工業株式会社 | Water electrolysis device and water electrolysis method |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58152834A (en) * | 1982-03-08 | 1983-09-10 | Asahi Chem Ind Co Ltd | Production of benzaldehyde |
| JP2007525593A (en) * | 2003-06-27 | 2007-09-06 | ゼネラル・モーターズ・コーポレーション | Photoelectrochemical device and electrode |
| JP2007239048A (en) * | 2006-03-09 | 2007-09-20 | Univ Of Electro-Communications | Light energy conversion apparatus and semiconductor photoelectrode |
| WO2013031063A1 (en) * | 2011-08-31 | 2013-03-07 | パナソニック株式会社 | Method for reducing carbon dioxide |
| WO2014068944A1 (en) * | 2012-10-31 | 2014-05-08 | パナソニック株式会社 | Photosemiconductor electrode, photoelectrochemical cell, and energy system |
| WO2014088077A1 (en) * | 2012-12-06 | 2014-06-12 | 昭和シェル石油株式会社 | Semiconductor electrode |
| WO2015001729A1 (en) * | 2013-07-05 | 2015-01-08 | パナソニックＩｐマネジメント株式会社 | Method for reducing carbon dioxide |
| WO2015087691A1 (en) * | 2013-12-13 | 2015-06-18 | 富士フイルム株式会社 | Artificial-photosynthesis array |
-
2015
- 2015-12-02 JP JP2015235513A patent/JP2017101288A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58152834A (en) * | 1982-03-08 | 1983-09-10 | Asahi Chem Ind Co Ltd | Production of benzaldehyde |
| JP2007525593A (en) * | 2003-06-27 | 2007-09-06 | ゼネラル・モーターズ・コーポレーション | Photoelectrochemical device and electrode |
| JP2007239048A (en) * | 2006-03-09 | 2007-09-20 | Univ Of Electro-Communications | Light energy conversion apparatus and semiconductor photoelectrode |
| WO2013031063A1 (en) * | 2011-08-31 | 2013-03-07 | パナソニック株式会社 | Method for reducing carbon dioxide |
| WO2014068944A1 (en) * | 2012-10-31 | 2014-05-08 | パナソニック株式会社 | Photosemiconductor electrode, photoelectrochemical cell, and energy system |
| WO2014088077A1 (en) * | 2012-12-06 | 2014-06-12 | 昭和シェル石油株式会社 | Semiconductor electrode |
| WO2015001729A1 (en) * | 2013-07-05 | 2015-01-08 | パナソニックＩｐマネジメント株式会社 | Method for reducing carbon dioxide |
| WO2015087691A1 (en) * | 2013-12-13 | 2015-06-18 | 富士フイルム株式会社 | Artificial-photosynthesis array |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2019107627A (en) * | 2017-12-20 | 2019-07-04 | 日本電信電話株式会社 | Semiconductor photoelectrode |
| WO2020153080A1 (en) * | 2019-01-25 | 2020-07-30 | シャープ株式会社 | Photocatalytic sheet |
| JPWO2020153080A1 (en) * | 2019-01-25 | 2021-11-25 | シャープ株式会社 | Photocatalyst sheet |
| JP7133040B2 (en) | 2019-01-25 | 2022-09-07 | シャープ株式会社 | photocatalyst sheet |
| WO2023089654A1 (en) * | 2021-11-16 | 2023-05-25 | 日本電信電話株式会社 | Production method for semiconductor photoelectrode |
| JP2023117608A (en) * | 2022-02-14 | 2023-08-24 | 本田技研工業株式会社 | Water electrolysis device and water electrolysis method |
| JP7466582B2 (en) | 2022-02-14 | 2024-04-12 | 本田技研工業株式会社 | Water electrolysis device and method |
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