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Title: Infrared-sensitive photocathode

Abstract

A single-crystal, multi-layer device incorporating an IR absorbing layer that is compositionally different from the Ga.sub.x Al.sub.1-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-y-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-x Sb, from which they are ejected into vacuum. Because the band alignments of Ga.sub.x Al.sub.1-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.

Inventors:
 [1];  [2]
  1. (Danville, CA)
  2. Pleasant Hill, CA
Issue Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
OSTI Identifier:
869818
Patent Number(s):
5404026
Assignee:
Regents of University of California (Oakland, CA)
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
infrared-sensitive; photocathode; single-crystal; multi-layer; device; incorporating; absorbing; layer; compositionally; 1-x; sb; electron; emitter; layers; envisioned; embodiment; limited; ability; grow; quality; material; chosen; substrate; non-exclusive; list; gasb; inas; 1-y-w; superlattices; absorption; photon; excites; conduction; band; absorber; externally; applied; electric; field; transports; electrons; ejected; vacuum; alignments; gaas; emitting; efficiencies; comparable; photocathodes; obtainable; provides; responsive; wavelengths; range; 10; conduction band; absorbing layers; electron emitter; electric field; chosen substrate; externally applied; applied electric; sb layer; absorbing layer; /257/

Citation Formats

Mariella, Jr., Raymond P., and Cooper, Gregory A. Infrared-sensitive photocathode. United States: N. p., 1995. Web.
Mariella, Jr., Raymond P., & Cooper, Gregory A. Infrared-sensitive photocathode. United States.
Mariella, Jr., Raymond P., and Cooper, Gregory A. Sun . "Infrared-sensitive photocathode". United States. https://www.osti.gov/servlets/purl/869818.
@article{osti_869818,
title = {Infrared-sensitive photocathode},
author = {Mariella, Jr., Raymond P. and Cooper, Gregory A},
abstractNote = {A single-crystal, multi-layer device incorporating an IR absorbing layer that is compositionally different from the Ga.sub.x Al.sub.1-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-y-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-x Sb, from which they are ejected into vacuum. Because the band alignments of Ga.sub.x Al.sub.1-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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1995},
month = {1}
}

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