Strain Engineered Electrically Pumped SiGeSn Microring Lasers on Si

Abstract

SiGeSn holds great promise for enabling fully group-IV integrated photonics operating at wavelengths extending in the mid-infrared range. Here, we demonstrate an electrically pumped GeSn microring laser based on SiGeSn/GeSn heterostructures. The ring shape allows for enhanced strain relaxation, leading to enhanced optical properties, and better guiding of the carriers into the optically active region. We have engineered a partial undercut of the ring to further promote strain relaxation while maintaining adequate heat sinking. Lasing is measured up to 90 K, with a 75 K T 0 . Scaling of the threshold current density as the inverse of the outer circumference is linked to optical losses at the etched surface, limiting device performance. Modeling is consistent with experiments across the range of explored inner and outer radii. These results will guide additional device optimization, aiming at improving electrical injection and using stressors to increase the bandgap directness of the active material.

Extended-SWIR GeSn LEDs with Reduced Footprint and Efficient Operation Power

“…Photodetector devices made of chemical vapor deposition (CVD) and molecular beam epitaxy (MBE) grown layers and heterostructures have been demonstrated to operate at wavelengths up to 4.6 μm in the mid-infrared (MIR) spectral range . While optically pumped GeSn-based lasers have been reported by many researchers recently, − experimental attempts to develop the electrically injected counterparts remain relatively scarce. − …”

Radiative Carrier Lifetime in Ge$_{1-x}$Sn$_x$ Mid-Infrared Emitters

“…Ge 1−x Sn x alloys constitute an emerging class of group IV semiconductors providing a tunable narrow bandgap, which has been highly attractive to implement scalable, silicon-compatible mid-infrared photonic and optoelectronic devices [1]. This potential becomes increasingly significant with the recent progress in nonequilibrium growth processes enabling high Sn content Ge 1−x Sn x layers and heterostructures leading to the demonstration of a variety of monolithic mid-infrared emitters and detectors [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Notwithstanding the recent developments in device engineering, the impact of structural characteristics on the basic behavior of charge carriers is yet to be fully understood.…”

Mid-infrared Imaging Using Strain-Relaxed Ge1–xSnx Alloys Grown on 20 nm Ge Nanowires

“…For instance, the growth using compositionally graded Ge 1−x Sn x buffers, where the amount of Sn is controlled by temperature and precursors flow, was found to be effective in partially relaxing the compressive strain by promoting the nucleation and glide of misfit dislocations in the underlying lower Sn content layers, while enhancing the Sn incorporation and preserving the high-quality of the topmost Sn-rich layer. 22−24 Although this growth protocol has been successful in producing device-quality materials, the high density of extended defects in the underlying layers remains a source of nonradiative recombination centers and leakage current in light emitters 2,4,6,[9][10][11]15,19 and photodetectors. 8,13,14,[16][17][18]25 Methods for defect and strain management using layer transfer, under etching, nanomembrane release, or wafer bonding were subsequently introduced to alleviate the harmful effects of lattice mismatch-induced extended defects leading to a clear improvement in the device performance.…”

“…Due to their narrow and tunable direct band, nonequilibrium group IV Ge 1– x Sn x alloys have attracted considerable interest as versatile silicon-compatible semiconductors for midwave infrared (MWIR) photonics and optoelectronics. − Epitaxy methods including molecular beam epitaxy (MBE) and chemical vapor deposition (CVD) are broadly used to grow these alloys on silicon wafers predominantly using Ge as an interlayer . However, these epitaxial Ge 1– x Sn x thin films still suffer inherent limitations due to the large lattice mismatch between Ge and Sn (≈14.7%) in addition to the low solubility of Sn in Ge (≈1 at.…”