Ge-Ge0.92Sn0.08 core-shell single nanowire infrared photodetector with superior characteristics for on-chip optical communication

Recent development on Ge1-xSnx nanowires with high Sn content, beyond its solid solubility limit, makes them attractive for all group-IV Si-integrated infrared photonics at the nanoscale. Herein, we report a chemical vapor deposition-grown high Sn-content Ge-Ge0.92Sn0.08 core-shell based single nanowire photodetector operating at the optical communication wavelength of 1.55 mu m. The atomic concentration of Sn in nanowires has been studied using x-ray photoelectron and Raman spectroscopy data. A metal-semiconductor-metal based single nanowire photodetector, fabricated via an electron beam lithography process, exhibits significant room-temperature photoresponse even at zero bias. In addition to the high-crystalline quality and identical shell composition of the nanowire, the efficient collection of photogenerated carriers under an external electric field results in the superior responsivity and photoconductive gain as high as similar to 70.8 A/W and similar to 57, respectively, at an applied bias of -1.0 V. The extra-ordinary performance of the fabricated photodetector demonstrates the potential of GeSn nanowires for future Si CMOS compatible on-chip optical communication device applications.

Automated summary

A single nanowire photodetector with a high Sn-content Ge-Ge0.92Sn0.08 core-shell structure, grown by chemical vapor deposition, exhibits superior performance at the optical communication wavelength of 1.55 μm, showcasing the potential of GeSn nanowires for future Si-integrated infrared photonics.