Investigation of optical characterizations in nitride semiconductor/metal hybrid nanostructures and their optoelectronic device applications

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K18110
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Applied materials; Nanostructural physics
• Research Institution: Yamagata University
• Principal Investigator: Oto Takao 山形大学, 大学院理工学研究科, 助教 (20749931)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: プラズモニック結晶 / ナノコラム / 表面プラズモン / 窒化物半導体 / 発光デバイス

Outline of Final Research Achievements

We fabricated InGaN based nanocolumn arrays with various column diameters and evaluate their structural and optical characterizations measured by electron microscopy and micro-spectroscopy measurements. By comparing the structural and optical characterizations, we systematically discussed the influence of the nanostructural effects on the optical characterizations. By investigating the strain relaxation and surface recombination in the InGaN nanocolumns both theoretically and experimentally, we made a significant contribution to the research field of semiconductor nanostructures.
Additionally, we achieved the light emission enhancement by introducing plasmonic crystals to the InGaN nanocolumn arrays. The mechanism of emission enhancement was originated from the standing wave of surface plasmon. The device-type InGaN based nanostructures was proposed toward high efficient plasmonic LEDs. We demonstrated the light emission enhancement at the lateral surface of the InGaN nanocolumns.

Free Research Field

ナノ構造物性

Academic Significance and Societal Importance of the Research Achievements

ナノ構造で発現する構造的な効果を積極的に利用することで，光電子デバイスの高性能化・多機能化に繋げることができるが，本研究では特に重要と考えられ，100 nm以下の細線化に伴って顕著に発現する歪緩和効果と表面再結合に焦点を当てた．これらの系統的な評価により，ナノ構造を用いた発光デバイスの高性能化を得るための設計指針に大きく貢献を果たしたと考えている．
また，窒化物半導体において橙～赤色領域は発光効率が非常に低いが，ナノ構造効果と表面プラズモン効果を同時に導入して，発光効率の向上に関する基盤技術を開拓した．この技術を応用・発展すれば，光学応答の制御や更なる発光効率の向上が期待できる．