Strain-relaxed GeSn-on-insulator (GeSnOI) microdisks

Abstract

GeSn alloys offer a promising route towards a CMOS compatible light source and the realization of electronic-photonic integrated circuits. One tactic to improve the lasing performance of GeSn lasers is to use a high Sn content, which improves the directness. Another popular approach is to use a low to moderate Sn content with either compressive strain relaxation or tensile strain engineering, but these strain engineering techniques generally require optical cavities to be suspended in air, which leads to poor thermal management. In this work, we develop a novel dual insulator GeSn-on-insulator (GeSnOI) material platform that is used to produce strain-relaxed GeSn microdisks stuck on a substrate. By undercutting only one insulating layer (i.e., Al2O3), we fabricate microdisks sitting on SiO2, which attain three key properties for a high-performance GeSn laser: removal of harmful compressive strain, decent thermal management, and excellent optical confinement. We believe that an increase in the Sn content of GeSn layers on our platform can allow us to achieve improved lasing performance.

1D photonic crystal direct bandgap GeSn-on-insulator laser

“…The limiting compressive strain in GeSn can be significantly relaxed during the undercut process while the contact with the SiO 2 layer allows for adequate thermal management and strong optical confinement simultaneously. 41 To confirm the relaxation of compressive strain in the released nanobeam, Raman spectroscopy was conducted. For Raman spectroscopy measurements, a 532-nm laser was focused on the nanobeam using the Â100 objective lens.…”

Room-Temperature Excitonic Nanolaser Array with Directly Grown Monolayer WS2

“…In Figure c, the lasing peak red-shifts by 0.1 nm on increasing the excitation. We believe that the red shift of the lasing peak in our Si 3 N 4 /WS 2 /Al 2 O 3 nanolaser with increasing pump power can be explained by the laser-induced heating effect and the increase of the crystal temperature . In Figure d, the PL emission intensity with the pump power as the independent variable ( L – L curve) is plotted for the 640.33 nm lasing mode.…”

Strain Engineered Electrically Pumped SiGeSn Microring Lasers on Si

“…From the design point of view, larger outer radii should allow reduction of the optical losses, but to fully leverage this the inner radius should also be increased accordingly. Furthermore, strain engineering 33 by silicon nitride stressors to induce tensile strain in the active GeSn region, that already enabled room temperature lasing under optical pumping, 15 provides a further path toward progress in the electrically pumped lasing temperature.…”