High responsivity near-infrared photodetectors in evaporated Ge-on-Si

V. Sorianello, A. De Iacovo, L. Colace, A. Fabbri, L. Tortora, E. Buffagni and G. Assanto

Appl. Phys. Lett. 101, 081101 (2012)


Germanium is considered the most suitable semiconductor for monolithic integration of near-infrared detectors on silicon photonic chips. Here we report on Ge-on-Si near-infrared photodetectors fabricated by thermal evaporation, demonstrating the use of phosphorus spin-on-dopant to compensate the acceptor states introduced by dislocations. The detectors exhibit 1.55??m responsivities as high as 0.1?A/W, more than two orders of magnitude larger than in undoped devices and comparing well with state-of-the-art p-i-n photodiodes. This approach enables simple and low-cost monolithic integration of near-infrared sensors with silicon photonics.