Patent US4211963A successfully refreshed from Google Patents.
Patent US4053920A successfully refreshed from Google Patents.
US4053920A
Expired / Lapsed
US
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Step graded photocathode
Assignee: United States Department of the Army
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Filing: 1976-12-21
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Granted: 1977-10-11
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Expires: 1996-12-21
Abstract
Abstract A method is provided for making an improved photocathode wherein a step ged substrate links a semitransparent cathode made from one p-type III-V compound or complex to a different III-V compound in the form of a host crystal.
Inventors
- 👤 Ronald E. Enstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:55
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/34; H01J2201/00; H01J2201/34; H01J2201/342; H01J2201/3421; H01J2201/3423
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
153 words
A III-V photocathode comprising host crystal of substantially pure III A V material; a series of graded layers of transition material approximately 2 microns thick and having a stochiometric formula III X A III 1-x B V M deposited on said host crystals, where the value of x is varied in steps to provide an abrupt increase of 8-10 mole percent of III A -V in each successive graded layer as compared with the underlying material, the last of said graded layers containing between 30 - 58 mole percent of III A V; final layer of said transition material containing 40 - 65 percent of III A V approximately 5 microns thick deposited over the last of said graded layers; and a photocathode layer composed of III-V compounds at least one of which is different from those in said transition material deposited on said final layer and activated with cesium vapor and oxygen.
Claim 2
Dependent Claim
153 words
A III-V photocathode comprising host crystal of substantially pure III A V material; a series of graded layers of transition material approximately 2 microns thick and having a stochiometric formula III X A III 1-x B V M deposited on said host crystals, where the value of x is varied in steps to provide an abrupt increase of 8-10 mole percent of III A -V in each successive graded layer as compared with the underlying material, the last of said graded layers containing between 30 - 58 mole percent of III A V; final layer of said transition material containing 40 - 65 percent of III A V approximately 5 microns thick deposited over the last of said graded layers; and a photocathode layer composed of III-V compounds at least one of which is different from those in said transition material deposited on said final layer and activated with cesium vapor and oxygen.
Claim 3
Dependent Claim
44 words
The photocathode according to Claim 1 wherein: the III A element is Indium; the III B element is Gallium; the V M element is Phosphorous; the III C element is Indium; the III D element is Gallium; and the V N element is Arsenic.
References Cited (Backward Citations)
US3995303A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-10-10 | 1981-04-11 | 1981-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-10 | 1985-04-11 | 1985-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-10 | 1989-04-11 | 1989-10-11 | $7700.00 | Window Closed / Lapsed |