High-performance p-i-n Ge on Si photodetectors for the near infrared: From model to demonstration

We have investigated the integration of Ge p-i-n and n-i-p heterojunction photodiodes on Si. Recognizing the crucial role of interface defects at the Ge/Si interface on the performance of photodetectors, we have designed and fabricated high-performance n-i-p Ge photodiodes on p(+)-Si substrates. These photodiodes exhibit short-circuit responsivities of 0.3 and 0.2 A/W at 1.3 and 1.55 mum, respectively, reverse dark currents of 20 mA/cm(2) and response times of 800 ps.