Abstract: In this monolithic detector array, a signal processing layer is epitaxially formed directly on an active detector layer. The active detector layer is supported by a transparent substrate. The three layers are made of intrinsic semiconductors of the same conductivity type (e.g., n-type). The semiconductor forming the active layer has a smaller bandgap than the signal processing and substrate layers. A plurality of vias of opposite conductivity type (e.g, p-type) extend through the signal processing layer into the active detector layer where they form p-n junctions with the active detector layer. These p-n junctions collect charges generated by the radiation and the vias conduct these charges to the signal processing layer where gates, AC background suppression circuitry, and a charge coupled device process the photogenerated signals.

Abstract: A low-leakage, heterojunction photodiode for use as a detector sensitive to infrared radiation is provided. The diode structure comprises a PbTe substrate of n-type conductivity with an n-type epitaxial buffer layer on the substrate and an epitaxial active layer on the buffer layer. The buffer layer is either Pb.sub.(1-x) S.sub.x Te or Pb.sub.1-x Se.sub.x Te with the atomic fraction of S or Se, x, being greater than 0 but less than 0.1. The active layer is Pb.sub.1-y Sn.sub.y Te with the atomic fraction of Sn, y, being greater than 0 but less than 0.3. There is a p-n junction created in the active layer with the n side of the junction being adjacent the buffer layer. Metal is deposited on the substrate and on the active layer to provide electrical contact to the diode.

Abstract: A method of making a junction in semiconductive materials to improve the spectral response of the junction in photovoltaic detectors. A first layer of semiconductive material is grown, by epitaxy technique, on a substrate of semiconductive material of the same conductivity type. Growth of the first layer is discontinued and the temperature is changed. Then a second layer of opposite conductivity type is grown on the first layer.

Abstract: A high speed infrared detector for use as a receiver in a 10.6.mu.m communication system and being composed of a Pb.sub.0.8 Sn.sub.0.2 Te crystalline substrate, a 10.6.mu.m absorbing layer on said substrate composed of a p-type Pb.sub.0.8 Sn.sub.0.2 Te material and a 10.6.mu.m transparent layer disposed on said first layer and composed of a Pb.sub.0.9 Sn.sub.0.1 Te n-type material.

Abstract: An inverted heterojunction photodiode for use as a laser detector sensitive to the 8 - 14 .mu.m portion of the infrared spectrum and operable above 77.degree. K. The diode structure comprises a PbTe substrate, a first buffer layer of a Pb.sub..90 Sn.sub..10 Te material on said substrate and a second active layer of a Pb.sub..80 Sn.sub..20 Te material on said buffer layer. The first and second layers are grown by liquid phase epitaxy.