Design and Simulation of Ge-on-Si Photodetectors with Electrically Tunable Spectral Response

Germanium-on-silicon technology has been thoroughly studied in the last 20 years and it now reached a high readiness level and it is mature for industrial development. In particular, germanium has been employed in a more-than-Moore pathway for the enhancement of silicon optical properties and the extension of the sensitivity spectrum of Si-based photodetectors. Typically, Ge-on-Si photodetectors exploit the extended visible to near-infrared absorption spectrum of Ge; we propose a dual diode Ge/Si structure where both semiconductors are used for the realization of photodetectors with a tunable sensitivity spectrum that can be completely electrically shifted from the visible to the near infrared wavelength range.