The authors have fabricated and tested heterojunction Ge/Si photodetectors based on pure Ge epitaxially grown on Si (001) using a two-step UHV-CVD process followed by cyclic thermal annealing. The detectors exhibit responsivities as high as 550mA/W at 1.32 mu m and 250mA/W at 1.55 mu m and response limes shorter than 850ps.
Masini, G., Colace, L., Assanto, G., Luan, H.c., Wada, K., Kimerling, L.c. (1999). High responsitivity near infrared Ge photodetectors integrated on Si. ELECTRONICS LETTERS, 35(17), 1467-1468 [10.1049/el:19991010].