Avalanche photodiodes (APDs) are used for detecting electromagnetic radiation ranging from visible light to gamma rays. They are more sensitive than conventional photodiodes because the photo generated carriers are multiplied inside the photodiode before signal read-out. The multiplication is done by impact ionization in a high electric field, generated by carefully adjusted doping profiles. APDs are used in receivers in optical communication, for gamma ray detection in PET-scanning, in scintillation detectors, and in laser range finders.

Commercially available APD device, supplied by OSIO, Norway.

The process for APD was developed at SINTEF in cooperation with a customer, resulting in devices with a gain of 100-150 at an operating voltage around 270-400 V. These APD chips are fabricated at MiNaLab with a customer specified process and are commercially available by OSI Optoelectronics, Norway.