Research on unexplored frequency quantum-cascade lasers using nitride semiconductors

2019 Fiscal Year Final Research Report

• Project/Area Number: 15H05733
• Research Category: Grant-in-Aid for Scientific Research (S)
• Allocation Type: Single-year Grants
• Research Field: Crystal engineering
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Hirayama Hideki 国立研究開発法人理化学研究所, 開拓研究本部, 主任研究員 (70270593)
• Co-Investigator(Kenkyū-buntansha): 鎌田 憲彦 埼玉大学, 理工学研究科, 教授 (50211173) ; 寺嶋 亘 国立研究開発法人理化学研究所, 平山量子光素子研究室, 研究員 (30450406)
• Project Period (FY): 2015-05-29 – 2020-03-31
• Keywords: 量子カスケードレーザー / 窒化物半導体 / 未開拓波長 / サブバンド間遷移 / テラヘルツ

Outline of Final Research Achievements

In this research, we aim to realize an unexplored frequency quantum-cascade lasers (QCLs) with frequency of 5 to 12 terahertz (THz) and with wavelength shorter than 3 μm by fabricating a QCL using a nitride semiconductor. We observed stimulated emission from GaN-based THz-QCL and confirmed the improvement of its operating temperature. The optical gain of GaN-based THz-QCL was analyzed based on the first-principles calculation. It was clarified that the optical gain sufficient for lasing is obtained at room temperature. We fabricated a GaN/AlGaN QCL on a Si substrate and lifted off the Si substrate to fabricate a double metal waveguide (DMW) type QCL. Current injection was performed and we observed the current-voltage characteristics that was analytically predicted.

Free Research Field

総合理工

Academic Significance and Societal Importance of the Research Achievements

本研究は、新規波長光デバイスの実現とそれらを実現する動作機構の物理的な理解に於いて学術的な意義が大きい。テラヘルツ光は、各種透視・非破壊検査用の光源として注目され、その応用範囲は、各種セキュリティ検査、火傷診断や癌細胞選別などの医療、電子産業、農業、各種工業、食品検査などと幅広い。また、近赤外-中赤外光は、光通信や環境計測を中心に応用範囲が広い。小型、連続動作、高出力が可能なTHz帯QCL、赤外QCLの未踏波長領域が実現すれば、応用分野の可能性は大きく広がり、我が国の経済発展への寄与が大きい。