Lasing in Group-IV materials

TL;DR

This paper reviews recent advances in mid-infrared silicon-compatible lasers, LEDs, and photodetectors based on Ge, GeSn, and SiGeSn alloys, highlighting their potential for integrated photonics in sensing and communication.

Contribution

It provides a comprehensive overview of the fundamental principles, material growth, and processing techniques for mid-IR group-IV photonic devices, emphasizing recent technological progress.

Findings

Development of Ge, GeSn, and SiGeSn based lasers and detectors

Insights into band structure modeling and material fabrication

Progress towards integrated mid-IR photonic platforms

Abstract

Silicon photonics in the near-Infra-Red, up to 1.6 um, is already one of key technologies in optical data communications, particularly short-range. It is also being prospected for applications in quantum computing, artificial intelligence, optical signal processing, where complex photonic integration is to be combined with large-volume fabrication. However, silicon photonics does not yet cover a large portion of applications in the mid-IR. In the 2 to 5 um wavelength range, environmental sensing, life sensing, and security all rely on optical signatures of molecular vibrations to identify complex individual chemical species. The markets for such analysis are huge and constantly growing, with a push for sensitivity, specificity, compactness, low-power operation and low cost. An all-group-IV, CMOS-compatible mid-IR integrated photonic platform would be a key enabler in this wavelength range. As for other wavelengths, such a platform should be complete with low-loss guided interconnects, detectors, modulators, eventually, and most importantly efficient and integrated light sources. This chapter reviews recent developments in the fields of mid-IR silicon-compatible optically and electrically pumped lasers, light emitting diodes and photodetectors based on Ge, GeSn and SiGeSn alloys. It contains insights into the fundamentals of these developments, including band structure modelling, material growth and processing techniques.