Point-contact germanium photocell

A Point-Contact Germanium Photocell with the unique properties of subminiature size (1/1000 cubic inch) and 360° sensitivity to near-infrared radiation has been developed to the production stage. The unit has a true glass fusion seal and good frequency response. We will describe testing methods which yield parameters from which the characteristic curves of the device can be reconstructed. It will be shown that for the desired axial geometry a minimum surface-to-bulk ratio and minimum dimensions yield maximum effective carrier lifetime and at the same time maximum sensitivity. Manufacturing and application problems will be discussed and typical optical assemblies shown.