Extrinsic silicon detector characterization

Abstract

A gallium doped extrinsic silicon (Si:Ga) photoconductive detector was tested for sensitivity and quickness of response. The developmental goal for this detector material was high speed operation without compromised detectivity (D*). The high speed, p-type infrared photoconductor, with photoconductive gain less than unity, was tested at 10.5 μm to determine an experimental value for the detectivity-bandwidth product of D*f* = 3.8 x 10¹⁸ cm-Hz³/²/W. Subsequently a theoretical model taking into account the optical absorption profile and majority carrier transport processes within the detector was developed which agreed with the experimental data.