Monolithic lasers on Si have long been anticipated as an enabler of full photonic integration, and significant progress in GeSn material development shows promise for such laser devices. While there are many reports focused on optically pumped lasers, in this work, we demonstrate electrically injected GeSn lasers on Si. We grew a GeSn/SiGeSn heterostructure diode on a Si substrate in a ridge waveguide laser device and tested it under pulsed conditions, giving consideration to the structure design to enhance the carrier and optical confinement. The peak linewidth of 0.13 nm (0.06 meV) and injection current curves indicated lasing, which was observed up to 100 K with emission peaks at 2300 nm. We recorded a threshold of 598A/cm2 at 10 K. The peak power and external quantum efficiency were 2.7 mW/facet and 0.3%, respectively. The results indicate advances for group-IV-based lasers, which could serve as a promising route for laser integration on Si.

GeSn lasers enable the monolithic integration of lasers on the Si platform using all-group-IV direct-bandgap material. The GeSn laser study recently moved from optical pumping into electrical injection. In this work, we present explorative investigations of GeSn heterostructure laser diodes with various layer thicknesses and material compositions. Cap layer material was studied by using Si 0.03 Ge 0.89 Sn 0.08 and Ge 0.95 Sn 0.05 , and cap layer total thickness was also compared. The 190 nm SiGeSn-cap device had threshold of 0.6 kA / cm 2 at 10 K and a maximum operating temperature ( T max ) of 100 K, compared to 1.4 kA / cm 2 and 50 K from 150 nm SiGeSn-cap device, respectively. Furthermore, the 220 nm GeSn-cap device had 10 K threshold at 2.4 kA / cm 2 and T max at 90 K, i.e., higher threshold and lower maximal operation temperature compared to the SiGeSn cap layer, indicating that enhanced electron confinement using SiGeSn can reduce the threshold considerably. The study of the active region material showed that device gain region using Ge 0.87 Sn 0.13 had a higher threshold and lower T max , compared to Ge 0.89 Sn 0.11 . The performance was affected by the metal absorption, free carrier absorption, and possibly defect density level. The maximum peak wavelength was measured as 2682 nm at 90 K by using Ge 0.87 Sn 0.13 in gain regions. The investigations provide directions to the future GeSn laser diode designs toward the full integration of group-IV photonics on a Si platform.

In this work, all group-IV band-to-band lasers based on SiGeSn/GeSn/SiGeSn multi-quantum-well structures were demonstrated. Lasing performance was investigated via two 4-well samples. The thinner GeSn well sample exhibits a maximum lasing temperature of 20 K and a threshold of 55 kW/cm² at 10 K, while the thicker well sample features a higher maximum operating temperature of 90 K and lower lasing thresholds of 25 and 62 kW/cm² at 10 and 77 K, respectively. The distinct results were tentatively interpreted mainly by the difference of gain volume. This result provides guidance for the future GeSn quantum well laser optimization for higher performance.

Owing to its true direct bandgap and tunable bandgap energies, GeSn alloys are increasingly attractive as gain media for mid-IR lasers that can be monolithically integrated on Si. Demonstrations of optically pumped GeSn laser operating at room temperature under pulsed excitation and at cryogenic temperature under continuous-wave excitation show great promise of GeSn lasers to be efficient electrically injected light sources on Si. Here we report electrically injected GeSn lasers using Fabry-Perot cavity with 20 μm, 40 μm, and 80 μm ridge widths. A lasing threshold of 0.756 kA/cm ² at 77 K, emitting wavelength of 2722 nm, and maximum operating temperature of 140 K were obtained. The lower threshold current density compared to previous works was achieved by reducing optical loss and improving the optical confinement. The peak power was measured as 2.2 mW/facet at 77 K.

Recent studies of SiGeSn materials and optoelectronic devices hold great promise for photonics integrated circuits (PICs) on Si platform featuring scalable, cost-effective, and power-efficient. Thanks to the breakthrough of low temperature material growth techniques, device-quality level materials have been grown, following by the demonstration of light-emitting diodes, photodetectors, and optically pumped and electrically injected band-to-band lasers. While the exciting developments in bulk devices were reported, the quantum wells (QWs) have been investigated targeting the dramatically improved and/or novel device performance via variety of quantum confinement effects. In this review, we summarize the recent progress on development of SiGeSn QWs, including the fundamental optical and transition studies and optoelectronic device applications. The inspirational results reveal the possibility of all-group-IV PICs with photonics and electronics monolithically integrated on a single-chip.

Group-IV alloy GeSn holds great promise for the high-performance optoelectronic devices that can be monolithically integrated on Si for near- and mid-infrared applications. Growth of GeSn using chemical vapor deposition technique with various Sn and Ge precursors has been investigated worldwide. To achieve relatively high Sn incorporation, the use of higher pressure and/or higher order Ge hydrides precursors were reported. In this work, we successfully demonstrated the growth of high-quality GeSn with Sn composition of 16.7% at low pressure of 12 Torr. The alloy was grown using the commercially available GeH₄ and SnCl₄ precursors via a chemical vapor deposition reactor. Material and optical characterizations were performed to confirm the Sn incorporation and to study the optical properties. The demonstrated growth results reveal a low-pressure growth window to achieve high-quality and high Sn alloys for future device applications.