Fabrication of potential step structures to improve energy conversion efficiency of photoelectrode

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K04708
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26050:Material processing and microstructure control-related
• Research Institution: Nagaoka University of Technology
• Principal Investigator: Nishikawa Masami 長岡技術科学大学, 工学研究科, 准教授 (20622393)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 窒素ドープ / 金属酸化物 / レーザ / 低温結晶化

Outline of Final Research Achievements

In a low-temperature nitridation process in which a precursor film in nitrogen plasma is irradiated with an excimer laser, it was found that by adding hydrogen to the nitrogen plasma, more nitrogen was introduced into the thin film, and metal oxide films doped with several at% nitrogen were successfully fabricated. This is thought to be due to the reduction effect of hydrogen and the generation of NH radicals. Furthermore, it was shown that the ease of nitrogen incorporation is related to the bond dissociation energy between the metal and oxygen, and the standard Gibbs energy of formation of oxides and nitrides. In particular, it was found that the smaller the bond dissociation energy of a metal, the easier it is to introduce nitrogen.

Free Research Field

材料プロセス

Academic Significance and Societal Importance of the Research Achievements

一般的に、金属酸化物に窒素ドープするには、窒素もしくはアンモニア雰囲気中での高温熱処理が必要であるのに対して、本プロセスは低温で窒素ドープ金属酸化物を成膜できることを明らかにした。本プロセスを用いることで、これまで困難であった耐熱性の低い材料（基材）にも窒素ドープ金属酸化物を成膜することが可能となる。つまり、窒素ドープ金属酸化物の応用が拡大する。今後は、本プロセスを用いて窒素ドープ金属酸化物を種々の材料に積層させることで、電位ステップ構造を実現させ、光電極等の特性向上を実現していく。