Clarification of mechanisms for photo-induced large conductivity change of graphene/diamond junctions and their device application

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01388
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 21060:Electron device and electronic equipment-related
• Research Institution: Waseda University
• Principal Investigator: Kenji Ueda 早稲田大学, 理工学術院(情報生産システム研究科・センター), 教授 (10393737)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: ダイヤモンド半導体 / グラフェン / 光伝導度変調 / メモリスタ

Outline of Final Research Achievements

Recently, we newly found that photoconductivity of vertically aligned graphene (VG)/diamond interfaces was drastically changed by photo-irradiation, and their photoconductivity values were memorized nonvolatility. In this study, we have tried clarifying the mechanism of the large photoconductivity change of VG/diamond interfaces and making their application for novel photo-devices.
As principal results for this study, following things were obtained. (1) interfacial structures of the VG/diamond junctions were clarified by high-resolution TEM measurements and their large photoconductivity change was found to be originated from redox reaction at the VG/diamond interfaces by movements of oxygen ions by electric field with light irradiation. (2) The VG/diamond interfaces were found to be used as novel neuromorphic devices which have photosensing, memory, and processing functions together.

Free Research Field

半導体材料・デバイス

Academic Significance and Societal Importance of the Research Achievements

本成果により、グラフェン(VG)／ダイヤモンド界面で多種多様な新機能・物性が現れる事及び、これらの新機能・物性を基にした新規デバイスの創製に繋がる事を示せた。また、本VG／ダイヤ素子を配列させてアレイ化する事で重要な画像（光）情報のみを記憶する脳機能模倣イメージセンサとして使える事も分かった為、本素子を更に改良して行く事で、将来的には重要な情報のみを選択的に記録する新型カメラ等の開発に繋がり、社会的にもインパクトが大きいと思われる。