Focal plane array with pixels defined by modulation of surface fermi energy

A method for fabricating a focal plane array (FPA) comprising:

• providing a substrate;
• providing a common contact layer on said substrate;
• providing an absorber layer on said common contact layer;
• providing a barrier layer on said absorber layer;
• providing a cap one layer on said barrier layer;
• providing a cap two layer on said cap one layer;
• selectively etching said cap two layer to delineate pixels of said FPA;
• providing a metal contact layer on said defined cap two layer;
• and
• providing a metal common contact layer to said common contact layer.

A high operating temperature midwave infrared focal plane array detector system comprising:

• a substrate layer comprising gallium antimonide (GaSb);
• a common conducting layer on said substrate;
• an absorber layer comprising a Type II superlattice;
• a barrier layer on said absorber layer, thickness of said barrier layer being between about 0.1 micron and about 0.5 micron, doping of said barrier layer being less than about 1e16 cm−3;
• a first cap layer comprising gallium antimonide (GaSb), thickness of said first cap layer being about 200 Angströms;
• a second cap layer comprising indium arsenide (InAs), said second cap layer etched to form gaps between pixels of said detector, thickness of said second cap layer being about 200 Angströms, depth of said gaps being about 200 Angströms;
• at least one metal contact pixel pad, photolithographically formed on top of each said pixel,
• wherein surface Fermi energy amplitude is about 250 meV,
• wherein optical fill-factor is about 100%,
• wherein spectrally averaged quantum efficiency is about 85% over a temperature range from about 80K to about 150K,
• wherein a noise-equivalent temperature difference does not exceed about 30 millikelvin up to an operating temperature of about 130 K with F/4 optics, and
• half maximum cutoff wavelength of about 5.1 microns.