JPS6268547A - Semiconductive photocatalyst - Google Patents
Semiconductive photocatalystInfo
- Publication number
- JPS6268547A JPS6268547A JP60206379A JP20637985A JPS6268547A JP S6268547 A JPS6268547 A JP S6268547A JP 60206379 A JP60206379 A JP 60206379A JP 20637985 A JP20637985 A JP 20637985A JP S6268547 A JPS6268547 A JP S6268547A
- Authority
- JP
- Japan
- Prior art keywords
- semiconductor
- type
- film
- semiconductors
- energy
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000011941 photocatalyst Substances 0.000 title claims abstract description 38
- 239000004065 semiconductor Substances 0.000 claims abstract description 157
- 238000006243 chemical reaction Methods 0.000 claims abstract description 22
- 238000006479 redox reaction Methods 0.000 claims description 3
- 239000012528 membrane Substances 0.000 abstract description 12
- 238000000034 method Methods 0.000 abstract description 3
- 238000002347 injection Methods 0.000 abstract description 2
- 239000007924 injection Substances 0.000 abstract description 2
- 238000010030 laminating Methods 0.000 abstract description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 13
- 230000031700 light absorption Effects 0.000 description 11
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 9
- 239000000969 carrier Substances 0.000 description 7
- 238000007254 oxidation reaction Methods 0.000 description 7
- 238000006722 reduction reaction Methods 0.000 description 7
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 6
- 239000004020 conductor Substances 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 6
- 229910052739 hydrogen Inorganic materials 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 238000000354 decomposition reaction Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 238000013032 photocatalytic reaction Methods 0.000 description 3
- 238000005268 plasma chemical vapour deposition Methods 0.000 description 3
- 230000001737 promoting effect Effects 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 238000009849 vacuum degassing Methods 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- WOCIAKWEIIZHES-UHFFFAOYSA-N ruthenium(iv) oxide Chemical group O=[Ru]=O WOCIAKWEIIZHES-UHFFFAOYSA-N 0.000 description 2
- 229910004613 CdTe Inorganic materials 0.000 description 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- 235000005311 Pandanus odoratissimus Nutrition 0.000 description 1
- 240000002390 Pandanus odoratissimus Species 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- -1 ZnO Chemical class 0.000 description 1
- 229910007709 ZnTe Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- UHYPYGJEEGLRJD-UHFFFAOYSA-N cadmium(2+);selenium(2-) Chemical compound [Se-2].[Cd+2] UHYPYGJEEGLRJD-UHFFFAOYSA-N 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 229910052976 metal sulfide Inorganic materials 0.000 description 1
- 239000012046 mixed solvent Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000006552 photochemical reaction Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 229910052702 rhenium Inorganic materials 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 150000004771 selenides Chemical class 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 150000004772 tellurides Chemical class 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
- B01J19/12—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electromagnetic waves
- B01J19/122—Incoherent waves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
-
- B01J35/30—
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
Abstract
Description
【発明の詳細な説明】
〔発明の技術分野〕
本発明は、光エネルギーを利用して化学反応を起こす半
導体光触媒に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a semiconductor photocatalyst that causes a chemical reaction using light energy.
光化学反応を利用して光エネルギーから化学エネルギー
へのエネルギー変換を行なう技術は、太陽光エネルギー
利用技術として近年注目を集めており、特に半導体物質
を用いた光触媒反応については活発に研究が進められて
いる。Technology that converts light energy into chemical energy using photochemical reactions has attracted attention in recent years as a solar energy utilization technology, and research is particularly active on photocatalytic reactions using semiconductor materials. There is.
例えば反応成分としての水と半導体光触媒を共存させた
反応系圧光を照射して、次式
で示される水の分解反応が、半導体光触媒の表面で行わ
れる事が知られている。For example, it is known that a reaction system in which water as a reaction component and a semiconductor photocatalyst coexist is irradiated with pressure light to cause a water decomposition reaction represented by the following formula to occur on the surface of the semiconductor photocatalyst.
つまり第３図に模式的に示す如く、反応成分としての水
と共存下で半導体光触媒（３）に光（２）を照射すると
価電子帯に正孔（ｈ＋）が、伝導帯に電子（ｅ−）がそ
れぞれ励起される。In other words, as schematically shown in Figure 3, when the semiconductor photocatalyst (3) is irradiated with light (2) in the presence of water as a reaction component, holes (h+) are generated in the valence band and electrons (e) are generated in the conduction band. -) are excited respectively.
この時半導体光触媒（３）が、第４図に示すように水の
還元レベルＢ （）（”／Ｈ２） よりも高い伝導帯
（４）のレベルを有するか、水の酸化レベルｇ（Ｏ□／
Ｈ２０）よりも低い価電子帯（５）のレベルを有するも
のであれば、光によって生成した電子、正孔は水を分解
して水素あるいは酸素を発生させることが熱力学的に可
能である。もちろん、両方の条件を満足していれば水素
と酸素を同時に発生させることも可能である。At this time, the semiconductor photocatalyst (3) has a conduction band (4) level higher than the water reduction level B()(''/H2) as shown in FIG. 4, or the water oxidation level g(O□ /
If it has a valence band (5) level lower than H20), it is thermodynamically possible for electrons and holes generated by light to decompose water and generate hydrogen or oxygen. Of course, it is also possible to generate hydrogen and oxygen simultaneously if both conditions are satisfied.
しかしながら、半導体光触媒には半導体の光吸収過程の
特質により、半導体のバンドギャップエネルギーより小
さいエレルギーに相当する波長域の光は有効に利用する
ことができず、光エネルギー変換効率を効果的に向上さ
せることができないという問題点がある。そのため、半
導体光触媒ができるだけ広い波長域にわたって光吸収領
域をもつように工夫しなければならない。However, due to the characteristics of the light absorption process of semiconductors, semiconductor photocatalysts cannot effectively utilize light in the wavelength range corresponding to energy smaller than the bandgap energy of semiconductors, which effectively improves the light energy conversion efficiency. The problem is that it cannot be done. Therefore, efforts must be made to make the semiconductor photocatalyst have a light absorption region over as wide a wavelength range as possible.
光吸収領域を広げる方法の１つとして、バンドギャップ
エネルギーの異なる複数の半導体を用いる方法が考えら
れる。本発明者等は、種々検討した結果、バンドギャッ
プエネルギーの異なる２橿以上の膜状半導体を積層した
構造の半導体光触媒を発明し、特許出願した（ｖｊ願昭
５８−２２３３３２号明細書）。本発明者達がさらに研
究を進めた結果、光吸収効率は良好となるものの、半導
体直接接合では、光照射により生じたキャリア（電子十
王孔）が接合界面で再結合を起こしやすく、酸化還元反
応に寄与する電子、正孔のエネルギー差、すなわち反応
に利用できるエネルギーが充分に得られないということ
がわかった。One possible method for expanding the light absorption region is to use a plurality of semiconductors with different band gap energies. As a result of various studies, the present inventors invented a semiconductor photocatalyst having a structure in which two or more film-like semiconductors having different band gap energies were stacked, and filed a patent application (VJ Application No. 58-223332). As a result of further research by the present inventors, although the light absorption efficiency was improved, in direct semiconductor bonding, carriers (electronic pores) generated by light irradiation are likely to recombine at the bonding interface, resulting in oxidation and reduction. It was found that the energy difference between electrons and holes that contribute to the reaction, that is, the energy that can be used for the reaction, is not sufficient.
さらに、本発明者等は、膜状半導体を導電体層を介して
接合することＫより、光吸収波長域を拡大しつつ各々の
半導体中に生じる電子、正孔の内、反応に寄与するキャ
リアを分離し、反応に寄与できるキャリアの損失を抑え
るとともに反応に利用できるエネルギーを充分に確保す
ることができることを見出し、特許出願した（特願昭５
９−２２７８２７号明細書）。この構造において重要な
点は、導電体層を介して存在する半導体層中に光照射に
よって発生したキャリアが効果的に導電体層に注入され
る必要があることである。このため、導電体７Ｉｉとし
ては、接合する半導体とオーミックコンタクトを形成す
る材料を使い、接合する半導体によってオーミックコン
タクトとなる材料が異なる場合には、それぞれの材料を
複合化する必要がある。Furthermore, the present inventors have discovered that by joining film-like semiconductors via a conductive layer, the light absorption wavelength range can be expanded, and carriers contributing to reactions among the electrons and holes generated in each semiconductor can be expanded. He discovered that it was possible to separate the carriers, suppress the loss of carriers that could contribute to the reaction, and secure sufficient energy that could be used for the reaction, and applied for a patent (patent application filed in 1973).
9-227827). An important point in this structure is that carriers generated by light irradiation in the semiconductor layer existing through the conductor layer need to be effectively injected into the conductor layer. Therefore, as the conductor 7Ii, a material that forms an ohmic contact with the semiconductor to be bonded is used, and if the material forming the ohmic contact differs depending on the semiconductor to be bonded, it is necessary to combine the respective materials.
通常オーミックコンタクト材料として金属を用いる場合
が多い為、光の損失は免れず、特に複合化した場合には
著しく半導体光触媒の高効率化を妨げる要因となってい
た。Since metal is usually used as an ohmic contact material, light loss is inevitable, and especially when composites are used, this has been a factor that significantly hinders the improvement of the efficiency of semiconductor photocatalysts.
本発明はかかる問題点に鑑みなされたもので、光吸収領
域を拡大することにより、光吸収効率が増大し、反応効
率が向上した半導体光触媒を提供することを目的とする
。The present invention was made in view of such problems, and an object of the present invention is to provide a semiconductor photocatalyst with increased light absorption efficiency and improved reaction efficiency by expanding the light absorption region.
本発明は、少なくともバンドギャップエネルギーの異な
るｐ型及びｎ型の膜状半導体を具備し、反応成分との共
存下で光照射により酸化還元反応を生じる複数の膜状半
導体からなり、前記膜状半導体をバンドギャップエネル
ギーの大きい順に入射光側より頭次積層しかつ前記ｐ型
及びｎ型の膜状半導体を高ドープ層を介してトンネル接
合したことを特徴とする半導体光触媒であり、また前記
ｐ型及びｎ型の膜状半導体が、ｐｎ接合又はｐｉｎ接合
の積層膜状半導体を構成するｐ型又はｎ型の膜状半導体
である半導体光触媒である。The present invention comprises at least p-type and n-type film-like semiconductors having different band gap energies, and is composed of a plurality of film-like semiconductors that undergo a redox reaction by light irradiation in coexistence with a reaction component, and the film-like semiconductor The semiconductor photocatalyst is characterized in that the p-type and n-type film semiconductors are stacked in order of increasing bandgap energy from the incident light side, and the p-type and n-type film semiconductors are tunnel-junctioned via a highly doped layer. and a semiconductor photocatalyst in which the n-type film semiconductor is a p-type or n-type film semiconductor constituting a pn junction or pin junction laminated film semiconductor.
つまり本発明はｐ型、ｎ型の膜状半導体、ｐｎ接合の積
層膜状半導体及びｐｉｎ接合の積層膜状半導体等の積層
構造からなる半導体光触媒であり、これらを接合する際
に高ドープ層を介してバンドギャップエネルギーの異な
るｐ型及びｎ型の膜状半導体をトンネル接合する事によ
り、各膜状半導体をオーミックコンタクト状態で良好に
接合したものである。In other words, the present invention is a semiconductor photocatalyst having a laminated structure such as p-type and n-type film semiconductors, pn junction laminated film semiconductors, pin junction laminated film semiconductors, etc. When joining these, a highly doped layer is formed. By tunnel-junctioning p-type and n-type film semiconductors having different band gap energies through the wafer, the film semiconductors are well bonded in an ohmic contact state.
次に本発明を、最も基本的な二層構造のものについて第
１図に示すバンド図を参照して説明する。Next, the present invention will be explained with reference to the band diagram shown in FIG. 1 for the most basic two-layer structure.
第１図（ａ）のｐ型の膜状半導体１１はＥ４のバンドギ
ャップエネルギーを有し、ｎｕの膜状半導体１２はＥｆ
ｈのバンドギャップエネルギーを有している。The p-type film semiconductor 11 in FIG. 1(a) has a bandgap energy of E4, and the nu film semiconductor 12 has a bandgap energy of Ef.
It has a bandgap energy of h.
このｐ型の膜状半導体１１とｎ型の膜状半導体１２とは
、高ドープｎ型領域１３及び高ドープｎ型領域１４から
なる高ドープ層を介して接合されており、これＫよって
ｐ型の膜状半導体１１とｎ型の膜状半導体１２とはトン
ネル接合となる。このため互いのキヤリア注入はオーミ
ックコンタクトと同様に機能する。すなわち前述のよう
に導電体層を介さず、オーミックコンタクトと同様の接
合が形成されることとなる。次に第１図（ｂ）を用いて
、前述の如き半導体光触媒の光触媒反応を説明する。な
お本発明においては、バンドギャップエネルギーの大き
い膜状半導体側から光を照射する必要がある為バンドギ
ャップエネルギーがＢｇｔ＞Ｅｌｈ のときｐ型の膜状
半導体１１側から光照射し、Ｂｇｔ＞Ｂｉｔ のときｎ
型の膜状半導体１２側から光照射する。The p-type film-like semiconductor 11 and the n-type film-like semiconductor 12 are bonded via a highly doped layer consisting of a highly doped n-type region 13 and a highly doped n-type region 14. The film-like semiconductor 11 and the n-type film-like semiconductor 12 form a tunnel junction. Therefore, mutual carrier injection functions similarly to ohmic contact. That is, as described above, a junction similar to an ohmic contact is formed without using a conductor layer. Next, the photocatalytic reaction of the semiconductor photocatalyst as described above will be explained using FIG. 1(b). In the present invention, since it is necessary to irradiate light from the side of the film-like semiconductor with a large band gap energy, when the band-gap energy is Bgt>Elh, light is irradiated from the side of the p-type film-like semiconductor 11, and when Bgt>Bit. time n
Light is irradiated from the film semiconductor 12 side of the mold.
例えばバンドギャップエネルギーがＢｇｔ ＞ Ｂｇｔ
の場合をｐＷの膜状半導体１１側から光２を照射すると
、膜状半導体１１および１２において電子、正孔が生成
され、膜状半導体１１で生じた正孔と膜状半導体１２で
生じた電子はそれぞれ高ドープ層の高ドープ型領域１３
及び高ドープｎ型領域１４に輸送されて再結合によって
消滅する。一方、膜状半導体１１で生じた電子は膜状半
導体１１の表面に輸送され、膜状半導体１２で生じた正
孔は膜状半導体１２の表面に４送されてそれぞれ酸化還
元反応に寄与する。For example, the band gap energy is Bgt > Bgt
When the light 2 is irradiated from the pW film semiconductor 11 side in the case of , electrons and holes are generated in the film semiconductors 11 and 12, and the holes generated in the film semiconductor 11 and the electrons generated in the film semiconductor 12 are are highly doped regions 13 of the highly doped layer, respectively.
and is transported to the highly doped n-type region 14 and annihilated by recombination. On the other hand, electrons generated in the membrane semiconductor 11 are transported to the surface of the membrane semiconductor 11, and holes generated in the membrane semiconductor 12 are sent to the surface of the membrane semiconductor 12, each contributing to an oxidation-reduction reaction.
この際上記電子と正孔とのΔＥのエネルギー差が、光触
媒反応の全エネルギー変化を決定する事となる。At this time, the energy difference of ΔE between the electron and hole determines the total energy change of the photocatalytic reaction.
以上のような半導体光触媒の機能を充分にひき出すため
には、半導体光触媒を構成する各膜状半導体に充分に光
が到達する必要があり、従来の金属等の導電体層を介在
させる構成の半導体光触媒に比較して、本発明の半導体
光触媒では導電体層を介在させない分だけ光の透過効率
が増大し、全体として半導体光触媒の反応効率を向上さ
せることが可能となる。In order to fully utilize the functions of a semiconductor photocatalyst as described above, it is necessary for sufficient light to reach each of the film-like semiconductors that make up the semiconductor photocatalyst. Compared to a semiconductor photocatalyst, the semiconductor photocatalyst of the present invention has an increased light transmission efficiency due to the absence of an intervening conductor layer, making it possible to improve the reaction efficiency of the semiconductor photocatalyst as a whole.
なお本発明における高ドープ層とは、接合されるｐ型及
びｎ型の膜状半導体の接合面近傍を膜状半導体自体より
高ドープ状態として、それぞれに高ドープｎ型領域（ｐ
＋）及び高ドープｎ型領域（ｎ＋）を設ける事により形
成され、トンネル接合状態となるものであればよい。通
常これらの高ドープ層は、不純物原子の熱拡散、イオン
インプランテーションあるいはＣＶＤ法におけるガス組
成の制御等によって得られ、目的とするオーミックコン
タクトを得るためにはキャリア濃度を１０”−１０”
ｃｍ−”にする必要がある。Note that the highly doped layer in the present invention refers to a highly doped layer in which the vicinity of the junction surface of the p-type and n-type film semiconductors to be joined is more highly doped than the film semiconductors themselves, and a highly doped n-type region (p
+) and a highly doped n-type region (n+) to form a tunnel junction state. Usually, these highly doped layers are obtained by thermal diffusion of impurity atoms, ion implantation, or controlling gas composition in CVD method, and in order to obtain the desired ohmic contact, the carrier concentration is set to 10"-10".
cm-".
また本発明に係る半導体光触媒は、バンドギャップエネ
ルギーが光の入射側よりその反対側に向かって連続的に
小さくなる膜状半導体を積層してもよい。すなわち、濃
度を変化させる等の手段を用いてバンドギャップエネル
ギーを連続的に変化させた膜状半導体を用いてもよい。Further, the semiconductor photocatalyst according to the present invention may be formed by laminating film-like semiconductors in which the band gap energy decreases continuously from the light incident side toward the opposite side. That is, a film-like semiconductor whose band gap energy is continuously changed by changing the concentration or the like may be used.
本発明に用いられる半導体としては、Ｓｉ、Ｇｅ等の他
にＩｎＰ！ ＧａＰＩ Ｚｎ３Ｐ２ ＨＡｌＡｓ ＋
ＧａＡｓ ＋ ＣｄＳ ＋ Ｚｎ Ｓ ＋ Ｃｕ、 Ｓ
＋ＣｄＳｅ、Ｚｎ８ｅ、ＣｄＴｅ、ＺｎＴｅ、ＴｉＯ
２，ＺｎＯ，５ｒＴｉＯ，、Ｆｅ２０ｇ等の金属リン化
物、金属砒化物、金属硫化物、金属セレン化物、金属テ
ルル化物、金属酸化物およびこれらを３元又は４元に組
み合せたＧａＡｌＡＳ ｌＩｎＧａＡｓ 、ＩｎＧａＡ
ｓＰ、ＧａＡＡ！ＡｓＰ、ＣｕＩｎＳ２． ＣｕＩｎＳ
ｅ、等が挙げられる。In addition to Si, Ge, etc., the semiconductor used in the present invention includes InP! GaPI Zn3P2 HAlAs +
GaAs + CdS + Zn S + Cu, S
+CdSe, Zn8e, CdTe, ZnTe, TiO
2. Metal phosphides, metal arsenides, metal sulfides, metal selenides, metal tellurides, metal oxides such as ZnO, 5rTiO, Fe20g, and ternary or quaternary combinations of these GaAlAS lInGaAs, InGaA
sP, GaAA! AsP, CuInS2. CuInS
e, etc.
また、本発明の半導体光触媒の片面もしくは両面に酸化
反応促進物質あるいは還元反応促進物質を担持すると、
反応効率を一層向上させることが可能となる。ここで酸
化反応促進物質とはＲｕＯ２。Furthermore, when an oxidation reaction promoting substance or a reduction reaction promoting substance is supported on one or both sides of the semiconductor photocatalyst of the present invention,
It becomes possible to further improve reaction efficiency. Here, the oxidation reaction promoter is RuO2.
Ｒｈ、Ｏ，等であり、還元反応促進物質とは、■ｒ、Ｑ
ｓ。Rh, O, etc., and the reduction reaction promoting substance is ■r, Q
s.
ｐｄ、ｐｔ、几ｈ＋ Ｒｕ 、 Ｒｅ 等である。pd, pt, 几h+Ru, Re, etc.
次に本発明の半導体光触媒を光吸収が非常に効果的な４
層構造のものについて第２図に示すバンド図を参照して
説明する。第２図（ａ）のｎ型の膜状半導体１１′及び
ｐ凰の膜状半導体１１はｐｎ接合の積層膜状半導体を形
成している。ｎｍの膜状半導体１１′はＢｇｔのバンド
ギャップエネルギーを有し、ｐ型の膜状半導体１１はＥ
ｇ；のバンドギャップエネルギーを有している。同様に
ｎ型の膜状半導体１２及びｐ型の膜状半導体１２′はｐ
ｎ接合の積層膜状半導体を形成し、ｎ型の膜状半導体１
２は８ｇ２のバンドギャップエネルギーを、ｐ型の膜状
半導体１２′は８ｇ２のバンドギャップエネルギーを有
している。Next, we will use the semiconductor photocatalyst of the present invention as 4, which is highly effective in light absorption.
The layered structure will be explained with reference to the band diagram shown in FIG. The n-type film semiconductor 11' and the p-type film semiconductor 11 shown in FIG. 2(a) form a pn junction laminated film semiconductor. The nm film semiconductor 11' has a bandgap energy of Bgt, and the p-type film semiconductor 11 has a bandgap energy of E.
It has a bandgap energy of g; Similarly, the n-type film semiconductor 12 and the p-type film semiconductor 12' are p
An n-junction laminated film semiconductor is formed, and an n-type film semiconductor 1 is formed.
2 has a bandgap energy of 8g2, and the p-type film semiconductor 12' has a bandgap energy of 8g2.
ｐ型の膜状半導体１１とｎ型の膜状半導体１２の界面に
は高ドープｎ型領域１３及び高ドープｎ型領域１４から
なる高ドープ層がそれぞれ形成されている。A highly doped layer consisting of a highly doped n-type region 13 and a highly doped n-type region 14 is formed at the interface between the p-type film semiconductor 11 and the n-type film semiconductor 12, respectively.
これらのバンドギャップエネルギーがＢｇ＋≧Ｅｇ；）
Ｂｇ２≧Ｅｇ′２のときｎ型の膜状半導体１１′側から
光２を照射する。光吸収領域の拡大という観点からは、
Ｅｇ＋ ＞ Ｅｇ： ＞ Ｅｇｚ ＞ Ｅｇ； であ
ることが好ましい。These band gap energies are Bg+≧Eg;)
When Bg2≧Eg'2, light 2 is irradiated from the n-type film semiconductor 11' side. From the perspective of expanding the light absorption area,
It is preferable that Eg+ > Eg: > Egz >Eg;
また、Ｅｇ＋ ＞Ｂｇ＋ ＋ Ｂｇｔ ＜Ｅｇｔ （Ｅ
ｇ＋とＥｇｘの大小関係は任意）の場合、゛すなわち高
ドープ層に向かっテＪ頁ｔｉにバンドギャップエネルギ
ーが小さくなるような場合にはｎｕの膜状半導体１１’
とｐ型の膜状半導体１２’との両側から光照射する。Also, Eg+ >Bg+ + Bgt <Egt (E
(The magnitude relationship between g+ and Egx is arbitrary), ``In other words, if the bandgap energy decreases toward the highly doped layer, then the nu film semiconductor 11'
Light is irradiated from both sides of the p-type film semiconductor 12'.
Ｂｇ＋≧Ｅｇｇ＞Ｂｇ２≧Ｅｇ１の場合、Ｅｇ；より小
さいエネルギーの光を吸収するためＢｇｔより小さいバ
ンドギャップエネルギーを有するｐ型の膜状半導体（図
示せず）を膜状半導体１２′の次に積層することもでき
る。また、Ｅｇ＋より大きいエネルギーに相当する波長
域の光はバンドギャップエネルギーがＥｇ＋のｎ型の膜
状半導体１どにより吸収されるが、Ｅｇｌよりかなり大
きなエネルギーをもつ光は有効に吸収することができな
いのでＢｇ＋より大きなバンドギャップエネルギーを持
つｎ型の膜状半導体（図示せず）をＥｇ＋の上に積層し
てもよい。In the case of Bg+≧Egg>Bg2≧Eg1, Eg: In order to absorb light with lower energy, a p-type film semiconductor (not shown) having a band gap energy smaller than Bgt is laminated next to the film semiconductor 12′. You can also. In addition, light in a wavelength range corresponding to an energy greater than Eg+ is absorbed by an n-type film semiconductor 1 with a bandgap energy of Eg+, but light with an energy considerably greater than Egl cannot be effectively absorbed. Therefore, an n-type film semiconductor (not shown) having a larger band gap energy than Bg+ may be laminated on Eg+.
このような４層ちるいは５１−構成の半導体光触媒では
ｐｎ接合の内部電場を利用することにより、光照射によ
り生じたキャリアの電荷分離効率を向上できる。In such a semiconductor photocatalyst having a four-layer structure or a 51-layer structure, the efficiency of charge separation of carriers generated by light irradiation can be improved by utilizing the internal electric field of the pn junction.
更に、２組のｐｎ接合を配置した構造であるため、光照
射を行なうと第２図（ｂ）に示すように相対的ＫｎＷの
膜状半導体１１′の７工ルミ準位がもち上がり、ｐ型の
膜状半導体１２′のフェルミ準位がおし下げられるので
、光照射状態においてｎ型の膜状半導体１１′の表面に
出る電子とｐ型の膜状半導体１２′の表面に出る正孔と
にΔＢのエネルギー差をもたせることが可能となり、こ
れが反応系の全エネルギー変化を決定することになる。Furthermore, since the structure has two sets of pn junctions, when light is irradiated, the 7-luminium level of the relative KnW film semiconductor 11' rises, as shown in FIG. Since the Fermi level of the type film semiconductor 12' is lowered, electrons appearing on the surface of the n-type film semiconductor 11' and holes appearing on the surface of the p-type film semiconductor 12' in the light irradiation state It becomes possible to have an energy difference of ΔB between the two, and this determines the total energy change of the reaction system.
また前述の説明ではｐｎ接合の積層膜状半導体を例にと
ったが、片側もしくは両側のｐｎ接合をｐｉｎ接合の積
層膜状半導体でおきかえることができる。Further, in the above description, a pn junction laminated film semiconductor was taken as an example, but the pn junction on one or both sides can be replaced with a pin junction laminated film semiconductor.
このように片側もしくは両側をｐｎ接合、 ｐｉｎ接合
の積層膜状半導体とする場合には、各積層半導体は同一
の半導体を用いドーパントを選択する事テよりｐ型、ｎ
型、ｉ型とする事が実用的である。In this way, when one side or both sides are made of a laminated film semiconductor with a pn junction or a pin junction, each laminated semiconductor is made of the same semiconductor and the dopant is selected, so that p-type, n-type
It is practical to use type i.
尚、本発明はバンドギャップエネルギーの異なるｐ型と
ｎ型の膜状半導体を具備するものであれば何層構成のも
のであってもよい。特に光の透過率、電荷分離効率等を
考慮すると、上述のような４層あるいは５ノー構造のも
のが好ましい。Note that the present invention may have any number of layers as long as it includes p-type and n-type film semiconductors having different band gap energies. In particular, in consideration of light transmittance, charge separation efficiency, etc., a four-layer or five-layer structure as described above is preferable.
以下に本発明の詳細な説明する。 The present invention will be explained in detail below.
実施例１
ｐ 、Ｗの膜状半導体としてのｐ型Ｓ１ ウェハの表
面ＫＰをドープしてｎ型の膜状半導体を形成し、バンド
ギャップエネルギー１．１ｅＶＯｐ型及びｎ型の膜状半
導体からなる積層膜状半導体を炸裂した。Example 1 The surface KP of the p-type S1 wafer as a film-like semiconductor of p and W was doped to form an n-type film-like semiconductor, and the band gap energy was 1.1eV. The film-like semiconductor exploded.
さらに前記ｎ型の膜状半導体長面を高ドープ状態にする
ため、キャリア密度１０” Ｃｍ−’程度までドープし
て高ドープｎ型領域を形成した。この高ドー７’ ｎ型
須截の上にプラズマＣＶＤ法を用イテバントギャップエ
ネルギー１．７ｅＶのａ−８ｉの高ドープｐ型領域−ｐ
型−１型−ｎ型を順番に積層し、ａ−３ｉ のｐｉｎ
接合の積層膜状半導体を形成した。このａ−３ｉのｐｉ
ｎ接合の積層膜状半導体とｓｉのｐｎ接合の積層膜状半
導体とは前記高ドープｎ型領域及び高ドープｎ型領域か
らなる高ドープ層によってトンネル接合となっている。Furthermore, in order to make the long surface of the n-type film-like semiconductor highly doped, a highly doped n-type region was formed by doping to a carrier density of about 10''Cm-'. A-8i highly doped p-type region-p with an itevant gap energy of 1.7 eV was prepared using plasma CVD method.
Stack type-1 type-n type in order, pin a-3i
A junction laminated film semiconductor was formed. This a-3i pi
The n-junction laminated film semiconductor and the Si pn junction laminated film semiconductor form a tunnel junction through the highly doped n-type region and the highly doped layer consisting of the highly doped n-type region.
さらにａ−８ｉのｎ型の膜状半導体の上に高エネルギー
の光を吸収するためバンドギャップエネルギー３．Ｏｅ
ＶのＴｉｏ、からなる膜状半導体を２００ＯＡ形成し、
七の上に還元反応を促進するためにＰｔ層を積層し、前
記ｓ１ウェハの晶面には酸化反応を促進するためにＲｕ
ｂ。Furthermore, since high-energy light is absorbed on the a-8i n-type film semiconductor, the band gap energy is 3. Oe
200 OA of film-like semiconductor made of Tio of V was formed,
A Pt layer is laminated on the s1 wafer to promote the reduction reaction, and a Ru layer is laminated on the crystal surface of the s1 wafer to promote the oxidation reaction.
b.
を積層して半導体光触媒を構成した。were stacked to form a semiconductor photocatalyst.
得られた半導体光触媒を反応成分としての水−メタノー
ル１：１混合溶媒中に浸漬し、真空脱気下においてｒｉ
ｏ、側より５００ Ｗ、Ｘ ｅランプを１０時間照射し
た。この時水の分解により発生した水素の量は４５μｍ
ｏｌであった。The obtained semiconductor photocatalyst was immersed in a 1:1 mixed solvent of water and methanol as a reaction component, and subjected to ri under vacuum degassing.
A 500 W X e lamp was irradiated from the o side for 10 hours. The amount of hydrogen generated by water decomposition at this time is 45μm
It was OL.
″実施例２
ｐ型の膜状半導体としてのｐ型ＧａＰウェハの表面にＳ
をドープしてｎ型の膜状半導体を形成し、バンドギャッ
プエネルギー２．３ｅＶＯｐ型及びｎ型の膜状半導体か
らなる積層膜状半導体を炸裂する。``Example 2 S on the surface of a p-type GaP wafer as a p-type film semiconductor
is doped to form an n-type film semiconductor, and a laminated film semiconductor consisting of a band gap energy of 2.3 eV Op type and an n-type film semiconductor is exploded.
さらに前記ｎ型の膜状半導体表面を高ドープ状態にする
ためキャリア密度１０２１園づ程度までドープし高ドー
プｎ型領域分形成した。この高ドープｎ型領域の上にプ
ラズマＣＶＤ法を用いてパンドギヤツプエネルギー１．
７ｅＶのａ−３ｉの高ドープｐ型領域−ｐ型〜ｉ型−ｎ
型を順番に積層し、ａ−３ｉのｐｉｎ接合の積層膜状半
導体を形した。このａ−３ｉのｐｉｎ接合の積層膜状半
導体とＧａＰのｐｎ接合の積ｆｆ！膜状半導体とは前記
の高ドープｎ型領域及び高ドープｎ型領域からなる高ド
ープ層によってトンネル接合となっている。さらに３−
３ｉのｎ型の膜状半導体の上に高エネルギーの光を吸収
するため、バンドギャップエネルギー３．ＯｅＶのＴｌ
Ｏ２からなる膜状半導体を２００ＯＡ形成し、その上に
還元反応を促進するためにｐｔ 層を積層し、前記基板
のＧａＰの裏面には酸化反応を促進するためにＲｕＯ□
を積層して半導体光触媒を構成した。Further, in order to make the surface of the n-type film-like semiconductor highly doped, the semiconductor was doped to a carrier density of about 1021 or so to form a highly doped n-type region. A plasma CVD method is used to deposit the highly doped n-type region with a gap energy of 1.
Highly doped p-type region of 7eV a-3i - p-type to i-type - n
The molds were laminated in order to form an a-3i pin junction laminated film semiconductor. Product ff of this a-3i pin junction laminated film semiconductor and GaP pn junction! The film-like semiconductor has a tunnel junction formed by the highly doped n-type region and the highly doped layer consisting of the highly doped n-type region. Further 3-
Since high energy light is absorbed on the n-type film semiconductor of 3i, the band gap energy 3. Tl of OeV
A 200 OA film-like semiconductor made of O2 was formed, a PT layer was laminated thereon to promote the reduction reaction, and RuO□ was layered on the back surface of the GaP of the substrate to promote the oxidation reaction.
were stacked to form a semiconductor photocatalyst.
得られた半導体光触媒を反応成分としての水−メタノー
ル１：１混合溶液中に浸漬し、真空脱気下においてＴｉ
ｅ、側ならびにＧａＰ側の両側から５００ＷＸｅ ラン
プを１０時間照射した。この時、水の分解により発生し
た水素の量は５５μｍｏｌであった。The obtained semiconductor photocatalyst was immersed in a 1:1 mixed solution of water and methanol as reaction components, and Ti was removed under vacuum degassing.
A 500WXe lamp was irradiated for 10 hours from both sides of the GaP side and the GaP side. At this time, the amount of hydrogen generated by water decomposition was 55 μmol.
比較例
ｐ型の膜状半導体としてｐ型Ｓｔ ウェハの表面にＰ
をドープしてｎ型の膜状半導体を形成し、バンドギャッ
プエネルギー１．１ｅＶＯｐ型ｎ型の膜状半導体からな
る積層膜状半導体を・作製する。このｎ型の膜状半導体
の土建導電体層としてＡ、ｕ−Ｇｅ層を形成し、オーミ
ックコンタクトを形成した。さらにこの上［４ｍ！体層
としてＡ１層を形成した後、プラズマＣＶＤ法を用いて
バンドギャップエネルギー１．７ｅＶのａＳｔのｐｉｎ
接合からなる積層膜状半導体を形成した。ａ−８ｉＯｐ
型の膜状半導体とＡ１層はえ−ミンクコンタクトを形成
している。ａ−３ｉのｎ型の膜状半導体の上には高エネ
ルギーの光を吸収するためバンドギャップエネルギー３
．０ｅＶＯＴ１０２からなる膜状半導体を２００ＯＡ形
成し、その上に還元反応を促進するためにＰｔ 層を触
媒として形成し、前記ＳＩ ウェハの裏面には酸化反
応を促進するためにＲ１３０２層を触媒として積層して
半導体光触媒を構成した。Comparative Example: p-type St as a p-type film semiconductor. P on the surface of a wafer.
is doped to form an n-type film semiconductor, and a laminated film semiconductor made of the n-type film semiconductor having a band gap energy of 1.1 eVOp is manufactured. An A, u-Ge layer was formed as a civil conductor layer of this n-type film semiconductor to form an ohmic contact. Furthermore above this [4m! After forming the A1 layer as the body layer, aSt pin with a band gap energy of 1.7 eV was formed using plasma CVD method.
A laminated film semiconductor consisting of junctions was formed. a-8iOp
The film-like semiconductor of the mold and the A1 layer form an e-mink contact. On the n-type film semiconductor of a-3i, there is a band gap energy of 3 to absorb high energy light.
．． A 200 OA film semiconductor made of 0eVOT102 was formed, a Pt layer was formed thereon as a catalyst to promote the reduction reaction, and an R1302 layer was laminated as a catalyst on the back side of the SI wafer to promote the oxidation reaction. A semiconductor photocatalyst was constructed.
得られた半導体光触媒を反応成分としての水−メタノー
ル１：１混合溶液中に浸漬し、真空脱気下において′ｒ
ｉＯ□側より５００ＷＸｅランプヲｌＯ時間照射した。The obtained semiconductor photocatalyst was immersed in a 1:1 mixed solution of water and methanol as a reaction component, and heated under vacuum degassing.
A 500WXe lamp was irradiated from the iO□ side for 10 hours.
この時、水の分解により発生した水素の社は３９μｍｏ
ｌであった。At this time, the amount of hydrogen generated by water decomposition was 39 μmo
It was l.
以上より明らかなように、本発明の実施例１゜２は共に
比較例より水素の発生量が多く有効な半導体光触媒であ
ることがわかる。As is clear from the above, both Examples 1 and 2 of the present invention are effective semiconductor photocatalysts that generate more hydrogen than the comparative example.
以上詳述した如く、本発明によれば光吸収領域が拡大し
、光吸収効率が増大し、電荷分離効率が向上しキャリア
が有効に利用でき、反応効率を著しく向上した半導体光
触媒を提供できる。As detailed above, according to the present invention, it is possible to provide a semiconductor photocatalyst in which the light absorption region is expanded, the light absorption efficiency is increased, the charge separation efficiency is improved, carriers can be used effectively, and the reaction efficiency is significantly improved.
第１図（ａ） （ｂ）及び第２図ｔａ） （ｂ）は本発
明に係わる半導体光触媒のバンド図、第３図は半導体光
触媒表面での水分解を説明するための図、第４図は第３
図のエネルギーバンド図である。
２・・光 ３ ・半導体光触媒４・・伝
導帯 ５・・価電子帯１１’、１２・・・ｎ
型の膜状半導体
１１ 、１２’ ・・ｐ型の膜状半導体１３ 高ドー
プｎ型領域 １４・・高ドープｎ型領域第 １
ド
）ＬＦｒＬＰ
第 ２ 図
第 ３ 図
第４図Figures 1 (a) (b) and 2 (ta) (b) are band diagrams of the semiconductor photocatalyst according to the present invention, Figure 3 is a diagram for explaining water splitting on the surface of the semiconductor photocatalyst, and Figure 4 is the third
It is an energy band diagram of the figure. 2..Light 3.Semiconductor photocatalyst 4..Conduction band 5..Valence band 11', 12...n
type film semiconductors 11, 12'...P-type film semiconductor 13 Highly doped n-type region 14...Highly doped n-type region 1
D) LFrLP Figure 2 Figure 3 Figure 4
Claims (2)
型及びｎ型の膜状半導体を具備し、反応成分との共存下
で光照射により酸化還元反応を生じる複数の膜状半導体
からなり、前記膜状半導体をバンドギャップエネルギー
の大きい順に入射光側より順次積層しかつ前記ｐ型及び
ｎ型の膜状半導体を高ドープ層を介してトンネル接合し
たことを特徴とする半導体光触媒。(1) At least p with different bandgap energy
It is composed of a plurality of film-like semiconductors that undergo a redox reaction by light irradiation in the coexistence with a reaction component, and the film-like semiconductors are arranged in order of increasing band gap energy from the incident light side. 1. A semiconductor photocatalyst, characterized in that the p-type and n-type film semiconductors are sequentially stacked and tunnel-junctioned via a highly doped layer.
ｎ接合の積層膜状半導体を構成するｐ型又はｎ型の膜状
半導体である事を特徴とする特許請求の範囲第１項記載
の半導体光触媒。(2) P-type and n-type film semiconductors are connected to p-n junction or pi
The semiconductor photocatalyst according to claim 1, which is a p-type or n-type film semiconductor constituting an n-junction laminated film semiconductor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60206379A JPH0628737B2 (en) | 1985-09-20 | 1985-09-20 | Semiconductor photocatalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60206379A JPH0628737B2 (en) | 1985-09-20 | 1985-09-20 | Semiconductor photocatalyst |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6268547A true JPS6268547A (en) | 1987-03-28 |
| JPH0628737B2 JPH0628737B2 (en) | 1994-04-20 |
Family
ID=16522360
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60206379A Expired - Lifetime JPH0628737B2 (en) | 1985-09-20 | 1985-09-20 | Semiconductor photocatalyst |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0628737B2 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08155309A (en) * | 1994-11-30 | 1996-06-18 | Riken Corp | Photodecomposition catalyst and its production |
| JP2008511435A (en) * | 2004-09-03 | 2008-04-17 | ジェン−エックス パワー コーポレイション | Electrochemical device |
| US7842393B2 (en) | 2006-12-27 | 2010-11-30 | Murakami Corporation | Vehicle antifogging element |
| JP2012046385A (en) * | 2010-08-27 | 2012-03-08 | Mitsubishi Chemical Holdings Corp | Electrode for water decomposition by light, method for producing the same and method for decomposing water |
| JP2016034611A (en) * | 2014-08-01 | 2016-03-17 | 株式会社デンソー | Semiconductor photocatalyst and artificial photosynthesis device applying the same |
| WO2018135144A1 (en) * | 2017-01-18 | 2018-07-26 | 日立化成株式会社 | Method for producing hydrogen gas, and method for producing semiconductor device |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4736267B2 (en) * | 2001-08-08 | 2011-07-27 | 住友金属鉱山株式会社 | Photocatalyst having catalytic activity even in the visible light region |
| JP4783686B2 (en) * | 2006-07-07 | 2011-09-28 | 独立行政法人科学技術振興機構 | III-V group nitride semiconductor, photocatalytic semiconductor element, photocatalytic oxidation-reduction reaction apparatus, and photoelectrochemical reaction execution method |
| JP4799450B2 (en) * | 2007-03-09 | 2011-10-26 | 株式会社東芝 | Photocatalyst complex and water purifier |
| JP4783869B2 (en) * | 2011-03-03 | 2011-09-28 | 独立行政法人科学技術振興機構 | III-V group nitride semiconductor, photocatalytic semiconductor element, photocatalytic oxidation-reduction reaction apparatus, and photoelectrochemical reaction execution method |
-
1985
- 1985-09-20 JP JP60206379A patent/JPH0628737B2/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08155309A (en) * | 1994-11-30 | 1996-06-18 | Riken Corp | Photodecomposition catalyst and its production |
| JP2008511435A (en) * | 2004-09-03 | 2008-04-17 | ジェン−エックス パワー コーポレイション | Electrochemical device |
| US7842393B2 (en) | 2006-12-27 | 2010-11-30 | Murakami Corporation | Vehicle antifogging element |
| JP2012046385A (en) * | 2010-08-27 | 2012-03-08 | Mitsubishi Chemical Holdings Corp | Electrode for water decomposition by light, method for producing the same and method for decomposing water |
| JP2016034611A (en) * | 2014-08-01 | 2016-03-17 | 株式会社デンソー | Semiconductor photocatalyst and artificial photosynthesis device applying the same |
| US9951429B2 (en) | 2014-08-01 | 2018-04-24 | Denso Corporation | Semiconductor photocatalyst and artificial photonic synthesis device having the same |
| WO2018135144A1 (en) * | 2017-01-18 | 2018-07-26 | 日立化成株式会社 | Method for producing hydrogen gas, and method for producing semiconductor device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0628737B2 (en) | 1994-04-20 |
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