USA As Represented by Secretary of the Navy

Marian E Hills

Nicholas Bottka

Josephine Covino

Howard Lessoff

Metal ternary sulfides of the general formula MM'.sub.2 S.sub.4 are synthesized by introducing stoichiometric amounts of nitrate precursors in concentrated nitric acid and heating to approximate dryness to yield a homogeneous powder mixture. The mixture is then exposed to a gaseous H.sub.2 S atmosphere under controlled conditions to produce the desired sulfide.

Metal ternary sulfides

A semiconductor multi-color filter spectrum analyzer is created by multiple pitaxial layers of varying composition. A DC sweep voltage is used to successively deplete the epitaxial layers. An AC voltage is used to modulate the absorption edge of the individual layers. A modification of this device concept is a variable bandwidth detector in which the spectral bandwidth is a function of the applied DC voltage.

Multi-color tunable semiconductor device

A quadrant avalanche photodiode with large surface areas is made using photolithographic planar technology. The use of proton bombardment creates semi-insulating material around the quadrants. Semi-insulating material prevents cross-talk between quadrants. The Schottky barrier quadrant detectors were fabricated using GaAs.sub.1-x Sb.sub.x ternary alloys grown epitaxially on heavily doped GaAs substrates.

Method of making avalanche photodiodes

A narrow two color semiconductor detector created from the built in field tween epitaxial layers due to interface traps. Opposite polarity on opposite sides of the interface result in a net photocurrent created on each side which flows in opposing directions. The substrate supporting the epitaxial layers provides a cutoff filter range for light entering through the substrate.

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Ridgecrest, CA, United States of America

Marian E Hills