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Advanced GeSn/SiGeSn Group IV Heterostructure Lasers
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.
Ge(Sn) nano-island/Si heterostructure photodetectors with plasmonic antennas
2020, Schlykow, Viktoria, Manganelli, Costanza Lucia, Römer, Friedhard, Clausen, Caterina, Augel, Lion, Schulze, Jörg, Katzer, Jens, Schubert, Michael Andreas, Witzigmann, Bernd, Schroeder, Thomas, Capellini, Giovanni, Fischer, Inga Anita
We report on photodetection in deep subwavelength Ge(Sn) nano-islands on Si nano-pillar substrates, in which self-aligned nano-antennas in the Al contact metal are used to enhance light absorption by means of local surface plasmon resonances. The impact of parameters such as substrate doping and device geometry on the measured responsivities are investigated and our experimental results are supported by simulations of the three-dimensional distribution of the electromagnetic fields. Comparatively high optical responsivities of about 0.1 A W-1 are observed as a consequence of the excitation of localized surface plasmons, making our nano-island photodetectors interesting for applications in which size reduction is essential. © 2020 The Author(s). Published by IOP Publishing Ltd.
CMOS-Compatible Bias-Tunable Dual-Band Detector Based on GeSn/Ge/Si Coupled Photodiodes
2021, Talamas Simola, Enrico, Kiyek, Vivien, Ballabio, Andrea, Schlykow, Viktoria, Frigerio, Jacopo, Zucchetti, Carlo, De Iacovo, Andrea, Colace, Lorenzo, Yamamoto, Yuji, Capellini, Giovanni, Grützmacher, Detlev, Buca, Dan, Isella, Giovanni
Infrared (IR) multispectral detection is attracting increasing interest with the rising demand for high spectral sensitivity, room temperature operation, CMOS-compatible devices. Here, we present a two-terminal dual-band detector, which provides a bias-switchable spectral response in two distinct IR bands. The device is obtained from a vertical GeSn/Ge/Si stack, forming a double junction n-i-p-i-n structure, epitaxially grown on a Si wafer. The photoresponse can be switched by inverting the bias polarity between the near and the short-wave IR bands, with specific detectivities of 1.9 × 1010 and 4.0 × 109 cm·(Hz)1/2/W, respectively. The possibility of detecting two spectral bands with the same pixel opens up interesting applications in the field of IR imaging and material recognition, as shown in a solvent detection test. The continuous voltage tuning, combined with the nonlinear photoresponse of the detector, enables a novel approach to spectral analysis, demonstrated by identifying the wavelength of a monochromatic beam. © 2021 The Authors. Published by American Chemical Society.