Electro-absorption modulation in GeSn alloys for wide-spectrum mid-infrared applications

Abstract

Silicon-based electronic-photonic integrated circuits, which are compatible with state-of-the-art complementary metal-oxide-semiconductor processes, offer promising opportunities for on-chip mid-infrared photonic systems. However, the lack of efficient mid-infrared optical modulators on silicon hinders the utilization of such systems. Here, we demonstrate the Franz-Keldysh effect in GeSn alloys and achieve mid-infrared electro-absorption optical modulation using GeSn heterostructures on silicon. Our experimental and theoretical results verify that the direct bandgap energy of GeSn can be widely tuned by varying the Sn content, thereby realizing wavelength-tunable optical modulation in the mid-infrared range with a figure-of-merit greater than 1.5 and a broadband operating range greater than 140 nm. In contrast to conventional silicon-photonic modulators based on the plasma dispersion effect, our GeSn heterostructure demonstrates practical and effective Franz-Keldysh mid-infrared optical modulation on silicon, helping to unlock the potential of electronic-photonic integrated circuits in a wide range of applications.

Controlling barrier height and spectral responsivity of p–i–n based GeSn photodetectors via arsenic incorporation

“…This also gives these prepared heterostructures the chance to be used as UV and IR photodetectors. 58 …”

Spark Discharge Synthesis and Characterization of Ge/Sn Janus Nanoparticles

“…Prototypes of lasers with electric and optical pumping functioning at temperatures of 90–270 K with emission peaks at 2.3–3.5 μm have been achieved on high-quality Ge/Sn films on germanium and silicon substrates by several groups [ 3 , 4 , 15 , 16 , 17 ]. The emission properties of Ge/Sn nanoparticles with segregated Sn nanoclusters on the surface of germanium nanoparticles [ 18 ], the usage of Ge/Sn layers for hybrid IR photodetectors [ 19 , 20 , 21 ] and adjustable optical modulators, functionalized from 1.8 to 5.0 μm [ 22 , 23 ], have also been demonstrated.…”

Dual-Step Selective Homoepitaxy of Ge with Low Defect Density and Modulated Strain Based on Optimized Ge/Si Virtual Substrate

“…In addition, the Ge lattice is well-matched with GaAs, which could be used as a buffer layer for the III-V integration in silicon photonics [ 8 ]. For other photonic material integration, the Ge buffer layer with high epitaxial quality is also necessary for the growth of GeSnSi materials with direct bandgap properties [ 9 , 10 , 11 , 12 , 13 ]. Growing high-quality Ge on Si is considered an effective approach to make full use of the traditional Si technology and reduce the costs of chips.…”