GeSnOI mid-infrared laser technology

Abstract

GeSn alloys are promising materials for CMOS-compatible mid-infrared lasers manufacturing. Indeed, Sn alloying and tensile strain can transform them into direct bandgap semiconductors. This growing laser technology however suffers from a number of limitations, such as poor optical confinement, lack of strain, thermal, and defects management, all of which are poorly discussed in the literature. Herein, a specific GeSn-on-insulator (GeSnOI) stack using stressor layers as dielectric optical claddings is demonstrated to be suitable for a monolithically integration of planar Group-IV semiconductor lasers on a versatile photonic platform for the near- and mid-infrared spectral range. Microdisk-shape resonators on mesa structures were fabricated from GeSnOI, after bonding a Ge0.9Sn0.1 alloy layer grown on a Ge strain-relaxed-buffer, itself on a Si(001) substrate. The GeSnOI microdisk mesas exhibited significantly improved optical gain as compared to that of conventional suspended microdisk resonators formed from the as-grown layer. We further show enhanced vertical out-coupling of the disk whispering gallery mode in-plane radiation, with up to 30% vertical out-coupling efficiency. As a result, the GeSnOI approach can be a valuable asset in the development of silicon-based mid-infrared photonics that combine integrated sources in a photonic platform with complex lightwave engineering.

Strong extended SWIR cavity resonances in a single GeSn nanowire

“…The optimized structure shows ~ 30% improved Q factors compared to the unoptimized nanowire at all simulated diameters because the optimized structure does not have the scattering site at a non-at facet. We believe that it may be feasible to achieve lasing in the optimized structure, possibly also by harnessing tensile strain to improve the material gain since the observed cavity resonances in our measurements already show a very narrow FWHM of ~ 3 nm that is is generally seen just before the lasing occurs 13,14,37 .…”

Room Temperature Lasing in GeSn Microdisks Enabled by Strain Engineering

“…[26][27][28] The main reason here for improved T L resides in the advantages of the layer transfer strategy as discussed in ref. [15] like the removal of interface defects. [16,17] As discussed in the introduction the tensile strain promotes the CB directness and shifts the laser transition from Γ-HH to Γ-LH.…”

“…This technology, demonstrated in refs. [13, 15] applied to the GeSn layer with Sn content of ≈17% led to room temperature laser emission. [ 16,17 ]…”

Impact of strain engineering and Sn content on GeSn heterostructured nanomaterials for nanoelectronics and photonic devices

“…When they reached a pump threshold density of 20 kW cm −2 at 75 K, they obtained a 2340 nm lasing line. 140 Yongduck Jung et al deposited 960 nm GeSn with 10% Sn content by relaxed growth deposition on Al 2 O 3 , followed by SiO 2 on Si. Then, Al 2 O 3 was selectively etched so that GeSn was stacked on SiO 2 .…”

“…The GeSn layer was conned between two stressor layers that act as barriers for the connement of carriers to enhance the GeSn emission. When they reached a pump threshold density of 20 kW cm À2 at 75 K, they obtained a 2340 nm lasing line 140. Yongduck Jung et al deposited 960 nm…”