US 6,633,125 B2 · Short wavelength infrared cathode

Abstract

A cathode structure for an image intensifier tube operates to extend the spectral range of an image intensifier to the short wavelength infrared (SWIR) range of the electromagnetic spectrum, which is between 1.0 to 1.75 μm. The cathode structure utilizes a multi-layer structure consisting of a layer of GaSb disposed upon a layer of GaAs. The layers form a heterojunction therebetween where the GaSb material absorbs radiation and the GaAs is for emission characteristics. The doping profiles in each material are used to maximize the effects of band gap offsets of the heterojunction as well as provide a nearly flat conduction band profile for the cathode structure. The condition of nearly flat conduction band is enhanced by the use of blocking contacts at the emission surface of the cathode, where a bias is applied.

Claims10

Dependent claims

A cathode for an image intensifier device for extending operation of said device to the short wavelength infrared (SWIR) range of the electromagnetic spectrum, comprising:

a multi-layer structure having a first layer of a SWIR absorbing material with an integral second layer of GaAs, the interface between said layers forming a heterojunction, the exposed major surface of said GaAs layer being heavily doped as compared to the rest of said second layer,
first and second blocking contacts disposed on said major surface and spaced apart, the space between said contacts creating an emitting surface area for said cathode when biased.

Dependencies are inferred from the claim text.

Short wavelength infrared cathode

Life of this patent

Short wavelength infrared cathode

Life of this patent

Abstract

Claims10