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Title: Infrared-sensitive photocathode

A single-crystal, multi-layer device is described incorporating an IR absorbing layer that is compositionally different from the Ga{sub x}Al{sub 1{minus}x}Sb layer which acts as the electron emitter. Many different IR absorbing layers can be envisioned for use in this embodiment, limited only by the ability to grow quality material on a chosen substrate. A non-exclusive list of possible IR absorbing layers would include GaSb, InAs and InAs/Ga{sub w}In{sub y}Al{sub 1{minus}y{minus}w}Sb superlattices. The absorption of the IR photon excites an electron into the conduction band of the IR absorber. An externally applied electric field then transports electrons from the conduction band of the absorber into the conduction band of the Ga{sub x}Al{sub 1{minus}x}Sb, from which they are ejected into vacuum. Because the band alignments of Ga{sub x}Al{sub 1{minus}x}Sb can be made the same as that of GaAs, emitting efficiencies comparable to GaAs photocathodes are obtainable. The present invention provides a photocathode that is responsive to wavelengths within the range of 0.9 {mu}m to at least 10 {mu}m. 9 figures.
Inventors:
;
Issue Date:
OSTI Identifier:
35052
Assignee:
Univ. of California, Oakland, CA (United States) PTO; SCA: 400500; PA: EDB-95:064829; SN: 95001365528
Patent Number(s):
US 5,404,026/A/
Application Number:
PAN: 8-004,766
Contract Number:
W-7405-ENG-48
Resource Relation:
Other Information: PBD: 4 Apr 1995
Research Org:
University of California
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; PHOTOCATHODES; DESIGN; CHEMICAL COMPOSITION; INFRARED RADIATION; GALLIUM ALLOYS; ALUMINIUM ALLOYS; ANTIMONY ALLOYS; INTERMETALLIC COMPOUNDS; OPTICAL PROPERTIES; GALLIUM ARSENIDES; PHOTOELECTRIC EMISSION

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