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DDC: 500 × Subject: lasers ×

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    Advanced GeSn/SiGeSn Group IV Heterostructure Lasers
    (Weinheim : Wiley-VCH, 2018) von den Driesch, Nils; Stange, Daniela; Rainko, Denis; Povstugar, Ivan; Zaumseil, Peter; Capellini, Giovanni; Schröder, Thomas; Denneulin, Thibaud; Ikonic, Zoran; Hartmann, Jean-Michel; Sigg, Hans; Mantl, Siegfried; Grützmacher, Detlev; Buca, Dan
    Growth and characterization of advanced group IV semiconductor materials with CMOS-compatible applications are demonstrated, both in photonics. The investigated GeSn/SiGeSn heterostructures combine direct bandgap GeSn active layers with indirect gap ternary SiGeSn claddings, a design proven its worth already decades ago in the III–V material system. Different types of double heterostructures and multi-quantum wells (MQWs) are epitaxially grown with varying well thicknesses and barriers. The retaining high material quality of those complex structures is probed by advanced characterization methods, such as atom probe tomography and dark-field electron holography to extract composition parameters and strain, used further for band structure calculations. Special emphasis is put on the impact of carrier confinement and quantization effects, evaluated by photoluminescence and validated by theoretical calculations. As shown, particularly MQW heterostructures promise the highest potential for efficient next generation complementary metal-oxide-semiconductor (CMOS)-compatible group IV lasers.
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    Dynamics of Broadband Lasing Cascade from a Single Dot-in-well InGaAs Microdisk
    ([London] : Macmillan Publishers Limited, part of Springer Nature, 2019) Talalaev, Vadim; Kryzhanovskaya, Natalia; Tomm, Jens W.; Rutckaia, Viktoriia; Schilling, Joerg; Zhukov, Alexey
    The development of a fast semiconductor laser is required for the realization of next-generation telecommunication applications. Since lasers operating on quantum dot ground state transitions exhibit only limited gain due to the saturation effect, we investigate lasing from excited states and compare its corresponding static and dynamic behavior to the one from the ground state. InAs quantum dots (QDs) grown in dot-in-well (DWELL) structures allowed to obtain light emission from ground and three excited states in a spectral range of 1.0–1.3 μm. This emission was coupled to whispering gallery modes (WGMs) of a 6 μm microdisk resonator and studied at room temperature by steady-state and time-resolved micro-photoluminescence. We demonstrate a cascade development of lasing arising from the ladder of quantum dot states, and compare the lasing behavior of ground and excited state emission. While the lasing threshold is being increased from the ground state to the highest excited state, the dynamic behavior is improved: turn-on times and lifetimes of WGMs become shorter paving the way towards high frequency direct driven microlasers. © 2019, The Author(s).