High-Bandwidth Extended-SWIR GeSn Photodetectors on Silicon Achieving Ultrafast Broadband Spectroscopic Response

Abstract

The availability of high-frequency pulsed emitters in the 2–2.5 μm wavelength range paved the way for a wealth of new applications in ultrafast spectroscopy, free-space and fiber-optical communications, surveillance and recognition, artificial intelligence, and medical imaging. However, developing these emerging technologies and their large-scale use depend on the availability of high-speed, low-noise, and cost-effective photodetectors. With this perspective, here we demonstrate GeSn photodiodes grown on silicon wafers featuring a high broadband operation covering the extended-SWIR range with a peak responsivity of 0.3 A/W at room temperature. These GeSn devices exhibit a high bandwidth reaching 7.5 GHz at 5 V bias with a 2.6 μm cutoff wavelength, and their integration in ultrafast time-resolved spectroscopy applications is demonstrated. In addition to enabling time-resolved electroluminescence at 2.3 μm, the high-speed operation of GeSn detectors was also exploited in the diagnostics of ultrashort pulses of a supercontinuum laser with a temporal resolution in the picosecond range at 2.5 μm. Establishing these capabilities highlights the potential of manufacturable GeSn photodiodes for silicon-integrated high-speed extended-SWIR applications.

High‐Speed Photodetectors on Silicon Photonics Platform for Optical Interconnect

“…Therefore, extending the range of PDs to longer or shorter wavelengths is also desirable in high‐speed PDs on silicon photonics platform. [ 248 ] In addition to the above discussed methods, there are a few other methods that have been used. One of them is strained semiconductor‐based PDs.…”

Theoretical Investigation of Strain-Adjustable Ge0.92Sn0.08 Light-Emitting Diodes With Giant Magnetostrictive Stressor for Short-Wave Infrared Light Source

“…Group-IV GeSn is compatible with CMOS processes and can be transformed into direct bandgap alloy, which is the promising material for short-wave infrared (SWIR) light source [4,5]. The Γ valley decreases faster than the L valley with the increase of introduced Sn, and the indirect-to-direct transition will be realized when Sn content reaches 7.1% [6][7][8][9], which can extend the applications such as electro-magnetic spectrum -based night vision and the optic window for the transcranial light [10][11][12][13]. However, it is difficult to increase the Sn content by more than 14% for light source material due to the Sn segregation caused by the low solid solubility (< 1%) of Sn in Ge and the large lattice mismatch [14][15].…”

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.…”