US4616248A
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UV photocathode using negative electron affinity effect in Alx Ga1 N
Assignee: Honeywell Inc
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Filing: 1985-05-20
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Granted: 1986-10-07
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Expires: 2005-05-20
Abstract
Abstract A high efficiency UV responsive negative electron affinity photocathode with the long wavelength cutoff tunable over the wavelength from ˜200 to ˜300 nm based on Al x Ga 1-x N. Negative electron affinity photocathodes for sharply enhanced photoemission yield can be formed by applying a layer of cesium to the surface of Al x Ga 1-x N for which the Fermi energy level is appropriately positioned.
Inventors
- 👤 M. Asif Khan
- 👤 Richard G. Schulze
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:05
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: 6
Claim 1
Independent Claim
62 words
In a UV photocathode detector comprising: a single crystalline basal plane sapphire (Al 2 O 3 ) substrate having a substantially planar major surface; a thin film epitaxial layer of aluminum gallium nitride (Al x Ga 1-x N) grown over said major surface where x>0; and, a monolayer thickness layer of cesium molecules evaporated over said Al x Ga 1-x N layer.
Claim 2
Dependent Claim
62 words
In a UV photocathode detector comprising: a single crystalline basal plane sapphire (Al 2 O 3 ) substrate having a substantially planar major surface; a thin film epitaxial layer of aluminum gallium nitride (Al x Ga 1-x N) grown over said major surface where x>0; and, a monolayer thickness layer of cesium molecules evaporated over said Al x Ga 1-x N layer.
Claim 3
Dependent Claim
27 words
The detector according to claim 1 in which said Al x Ga 1-x N epitaxial layer is in the thickness range of 100 nm to 1000 nm.
Claim 4
Dependent Claim
80 words
In a photocathode detector comprising: a single crystalline basal plane sapphire (Al 2 O 3 ) substrate having a substantially planar major surface; a thin film epitaxial layer of high conductivity gallium nitride (GaN) grown on said major surface; a cathode contact to said GaN layer; a thin film epitaxial Al x Ga 1-x N layer grown over said GaN layer where x>0; and, a monolayer thickness layer of cesium molecules evaporated over said Al x Ga 1-x N layer.
Claim 5
Dependent Claim
80 words
In a photocathode detector comprising: a single crystalline basal plane sapphire (Al 2 O 3 ) substrate having a substantially planar major surface; a thin film epitaxial layer of high conductivity gallium nitride (GaN) grown on said major surface; a cathode contact to said GaN layer; a thin film epitaxial Al x Ga 1-x N layer grown over said GaN layer where x>0; and, a monolayer thickness layer of cesium molecules evaporated over said Al x Ga 1-x N layer.
Claim 6
Dependent Claim
47 words
The detector according to claim 4 in which said GaN epitaxial layer is in the thickness range of about 100 nm to about 1000 nm and said Al x Ga 1-x N epitaxial layer is in the thickness range of about 100 nm to about 1000 nm.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-10-06 | 1990-04-07 | 1990-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-10-06 | 1994-04-07 | 1994-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-10-06 | 1998-04-07 | 1998-10-07 | $7700.00 | Window Closed / Lapsed |