Camera having a reduced dark current photodetector

A camera comprising:

• an integrated dewar cooler assembly (IDCA) having an optical window;
• a photodetector disposed within the IDCA to receive light passing through the optical window the photodetector comprising:
• a photo absorbing layer comprising a p-doped semiconductor exhibiting a valence band energy and a conducting band energy during operation of the photo-detector;
• a barrier layer comprising a semiconductor, a first side of the barrier layer adjacent a first side of the photo absorbing layer, the barrier layer exhibiting a conduction band energy level substantially equal to the conduction band energy level of the photo absorbing layer and a valance band energy level exhibiting an energy gap in relation to the valance band of the photo absorbing layer, the energy gap being sufficient to minimize charge carriers tunneling and thermalization;
• and,
• a contact layer comprising a doped semiconductor, the contact layer adjacent a second side of the barrier layer opposing the first side;
• the barrier layer exhibiting a thickness, the thickness and the band gap being selected to be sufficient to minimize tunneling of holes between the photo absorbing layer and the contact layer and substantially block the flow of thermalized holes between the photo absorbing layer and the contact layer.

A camera comprising:

• an integrated dewar cooler assembly (IDCA) having an optical window;
• a photodetector disposed within the IDCA to receive light passing through the optical window the photodetector comprising:
• a photo absorbing layer comprising a doped semiconductor exhibiting a valence band energy and a conducting band energy during operation of the photo-detector;
• a contact layer comprising a doped semiconductor exhibiting a valence band energy and a conducting band energy during operation of the photo-detector;
• a barrier layer comprising a charge carrier compensated semiconductor, the barrier layer having an energy band gap and associated conduction and valence band energies, the barrier layer being charge compensated by doping impurities introduced thereto, such that it exhibits a valence band energy level substantially equal to the valence band energy level of the photo absorbing layer and a conduction band energy level exhibiting a significant band gap in relation to the conduction band of the photo absorbing layer, a first side of the barrier layer adjacent a first side of the photo absorbing layer, and the contact layer being adjacent a second side of the barrier layer opposing the first side;
• wherein the relationship between the photo absorbing layer and contact layer valence and conduction band energies and the barrier layer conduction and valance band energies is selected to facilitate minority carrier current flow while inhibiting majority carrier current flow between the contact and photo absorbing layers.