Metal contact free photodetector with sidewall doping

A photodetector comprising:

• a waveguide absorption region for mounting in a device layer of a photonic integrated circuit (PIC) for transmitting an optical signal;
• a p-type contact in the device layer on one side of the waveguide absorption region, the p-type contact comprising a first p-type portion including a first p-type doping concentration and a second p-type portion including a second higher p-type doping concentration adjacent to the first p-type portion;
• an n-type contact in the device layer on an opposite side of the waveguide absorption region, the n-type contact comprising a first n-type portion including a first n-type doping concentration adjacent to the waveguide absorption region, and a second n-type portion including a second higher n-type doping concentration adjacent to the first n-type portion;
• an absorbing body on top of the waveguide absorption region for converting the optical signal to an electrical signal, the absorbing body including a first sidewall portion including a p-type dopant at least partially overlapping the first p-type portion and not in contact with the second p-type portion, and a second sidewall portion including an n-type dopant at least partially overlapping the first n-type portion not in contact with the second n-type portion;
• a first terminal extending from the second p-type portion for transmitting the electrical signal to external circuitry;
• and
• a second terminal extending from the second n-type portion for transmitting the electrical signal to the external circuitry.