Study of Si-Based GeSn Optically Pumped Lasers With Micro-Disk and Ridge Waveguide Structures

A silicon-based monolithic laser has long been desired. Recent demonstration of lasing from direct bandgap group-IV alloy GeSn has opened up a completely new approach that is different from the traditional III-V integration on Si. In this study, high-quality GeSn samples were grown using a unique spontaneous Sn-enhanced growth recipe with an Sn composition as high as ∼20.0%. GeSn lasers based on waveguide Fabry-Pérot and micro-disk cavities were fabricated and characterized. The waveguide features better local heat dissipation, while the micro-disk offers stronger optical confinement plus strain relaxation. The maximum operating temperature of 260 K was achieved from a waveguide laser, and a threshold of 108 kW/cm 2 at 15 K was achieved from a micro-disk laser. A peak lasing wavelength of up to 3.5 µm was obtained with a 100-µm-wide ridge waveguide laser.