About this Research Topic
Silicon has been a miracle material for the electronics industry, a major factor in driving the digital revolution. At the same time, there has been a parallel effort to broaden the reach of Si technology by expanding its functionalities well beyond electronics. Si is now being increasingly investigated as a platform for building photonic devices. The field of Si photonics has seen impressive growth since the early 1980s. Indeed, the vast infrastructure of the global Si electronics industry is expected to benefit the fabrication of highly sophisticated Si photonic devices at costs that are lower than those currently required for compound semiconductors. Furthermore, Si-based photonic devices make possible the monolithic integration of photonic devices with high-speed Si electronics, thereby setting the stage for an upcoming Si-based optoelectronic revolution.
Over past a few decades, tremendous investments have been made to search for a viable solution for monolithic integrated Si-based optoelectronics. The most challenging task has been the fabrication of an efficient light source, as well as high-performance light detection using compatible technology. It is therefore highly desirable to develop a transformative strategy for Si-based lasers and detectors.
For a long time, theoretical studies have suggested that the group-IV alloy SiGeSn should possess a tunable bandgap, and eventually a direct bandgap. Not until recently have device-quality SiGeSn materials been grown and characterized, establishing a solid foundation for the development of Si-based optoelectronics devices. Some key strategic attributes offered by SiGeSn materials are:
i) The ability to independently tune the lattice constant and bandgap by simultaneously varying the compositions of Si, Ge, and Sn;
ii) The availability of a true direct bandgap group-IV material;
iii) The possibility of forming desirable type-I band alignment to provide a favorable quantum confinement for the design of optoelectronics;
vi) The potential to cover near-IR wavelengths up to 12 μm through band-to-band transition, and all wavelengths beyond 12 μm through inter-subband transition;
v) A low material growth temperature below 400ºC fully compatible with CMOS process; and
vi) The feasibility of selective area growth, which is highly desirable for optoelectronic integration.
The purpose of this Research Topic is to publish quality research papers as well as review articles presenting original research on cutting-edge SiGeSn technology for mid-infrared applications, including the growth of the material and demonstrations of optoelectronic devices such as emitters and photodetectors. Suggested themes include, but are not limited to:
- Study of material growth mechanism
- Characterization of material properties
- Characterization of optical properties
- Development of SiGeSn/GeSn-based emitters and detectors
- Development of SiGeSn/GeSn-based passive devices
- Exploring the all-group-IV on-chip integration solution
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