Development of bright excitons with long lifetime for quantum information devices

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K18731
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 21:Electrical and electronic engineering and related fields
• Research Institution: Kyushu University
• Principal Investigator: Itagaki Naho 九州大学, システム情報科学研究院, 教授 (60579100)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Keywords: 酸化物半導体 / スパッタリング / 結晶成長 / 量子構造 / エキシトン

Outline of Final Research Achievements

The purpose of this study is to realize bright excitons with long lifetime using a strained quantum well structure based on ZnO related materials. Conventional bright excitons are highly controllable by light but have short lifetimes, while dark excitons have long lifetimes but are difficult to control with light. This study aims to extend the lifetime of bright excitons using strained quantum wells consisting of ZnO materials. We have realized high-quality ZnMgO/ZnO heterointerfaces on sapphire substrates, which are key to achieving long-lived bright excitons, and confirmed exciton absorption and emission even at room temperature. Based on these results, we are currently fabricating ZnO/ZnMgO strained quantum wells and verifying their functionality as quantum bits.

Free Research Field

電子材料，プラズマエレクトロニクス

Academic Significance and Societal Importance of the Research Achievements

本研究は，ZnO系半導体材料からなる歪量子井戸が，従来の明暗励起子において存在した寿命と制御性のトレードオフ問題を解決し，励起子研究に新たな変革点・転換点をもたらすと考え構想に至ったものである．励起子を「電子と正孔が再結合する過程 (=中間状態）としての準粒子」として扱い，受発光を伴うその生成と消滅に着目した工学的応用を行ってきたこれまでの励起子研究を転換させる点で，学術的意義を有する．また，明るい長寿命励起子の開発は，大規模集積化において有利な「光」によるデータ伝送を前提とした量子コンピュータの実現の一助となるものであり，実用的観点からも意義を有する．