A silicon-germanium W-structure photodiode for near-infrared detection

Abstract

The authors report on the design, characterization, and performance of silicon-rich SiGe waveguide photodetectors grown directly on silicon without virtual buffer relaxation layers. The type-II band offsets of the SiGe system is used to engineer a "W-structure" for absorption at 1.3 m. Multimode waveguide devices are found to have a responsivity of 13.2 mA/ W and a specific detectivity of 1.8ϫ 10 8 cm Hz 1/2 W −1 at 1.3 m. Variation in the responsivity versus length of single-mode waveguide devices was used to characterize the material, yielding an optical absorption coefficient of 11.21 cm −1 for a single active region that is 25 Å thick. The 500 m long single-mode devices exhibit a 3 dB bandwidth of 1.54 GHz.

Modelling of the Quantum Transport in Strained Si/SiGe/Si Superlattices Based P-i-n Infrared Photodetectors for 1.3 - 1.55 μm Optical Communication

“…Figure 9 shows the dark current density without excitation and the current density with excitation caused by external influences such as the optical excitation with photons or impact ionization under large electric fields of a typical device shown in Figure 1(b). In order to obtain the best agreement between experimental values and numerical simulation, we showed that the performed calculations have good correlation with experimental results [34,35], and the weak dependence of dark current peak shift are explained by the difference of offset values in each devices. Figure 10 shows the calculated energy The Fermi levels and the e 1 and hh 1 quantum levels are drawn with their relative wave functions.…”