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SiGeSn Ternaries for Efficient Group IV Heterostructure Light Emitters


The inability of group IV elements silicon (Si) and germanium (Ge), which build the backbone of nowadays electronic circuits, to efficiently generate light, impedes large scale integration of optoelectronics.

Adding the heavier group IV element tin (Sn) to the mixture has helped to overcome this obstacle, as optical-pumped lasing at around 2.2 µm has previously been observed in Si-congruent GeSn alloys (Wirths and Geiger et al., Nature Photonics 2015). Efficient electrically-driven light emitters, such as LEDs and lasers, additionally require larger-bandgap materials to confine the injected carriers in the active region to allow for their efficient radiative recombination.

Researchers from the Forschungszentrum Jülich (Germany), in cooperation with international partners from Paul Scherrer Institute (Switzerland), University of Leeds (United Kingdom) and CEA-Leti (France), have investigated the ternary group IV alloy SiGeSn for this purpose. By independent tuning of Si and Sn content they were able to engineer the material’s bandgap in short-wave infrared spectrum of up to about 2.6 µm. The broad range of possible alloys may allow a huge diversity of applications. Besides their use as passive layers, they may also provide alternative active layers for detector applications in the mid-infrared spectrum, or allow solely ternary-based light emitters.
To really prove SiGeSn to be a promising material, the researchers implemented it as barrier material in a GeSn/SiGeSn multi quantum well heterostructure. Fully CMOS-compatible processing of LEDs yielded strong electrically-driven room temperature light emission, substantiating their use in future efficient group IV optoelectronics.

SiGeSn TernariesGeSn/SiGeSn multi quantum well heterostructure
Copyright: Forschungszentrum Jülich

Article: Nils von den Driesch et al: SiGeSn Ternaries for Efficient Group IV Heterostructure Light Emitters

Article: Daniela Stange et al.: Short-wave infrared LEDs from GeSn/SiGeSn multiple quantum wells


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