Infrared-sensitive photocathode

Patent · Tue Apr 04 04:00:00 EDT 1995

OSTI ID:35052

Mariella, Jr, R P; Cooper, G A

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.

• Research Organization: University of California
• DOE Contract Number: W-7405-ENG-48
• Assignee: Univ. of California, Oakland, CA (United States)
• Patent Number(s): US 5,404,026/A/
• Application Number: PAN: 8-004,766
• OSTI ID: 35052
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ALUMINIUM ALLOYS
ANTIMONY ALLOYS
CHEMICAL COMPOSITION
DESIGN
GALLIUM ALLOYS
GALLIUM ARSENIDES
INFRARED RADIATION
INTERMETALLIC COMPOUNDS
OPTICAL PROPERTIES
PHOTOCATHODES
PHOTOELECTRIC EMISSION