US3872489A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron emission from a cold cathode
Assignee: Verizon Laboratories Inc
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Filing: 1973-02-22
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Granted: 1975-03-18
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Expires: 1993-02-22
Abstract
Abstract An electron emitter comprising a body of a wide band gap material using double injection space-charge limited current. By using double injection of carriers to establish space-charge limited currents in high resistivity p-type semiconductors, the number of minority carriers can be increased considerably without raising the Fermi level above mid band gap. By using such double injection space-charge limited current a sufficient amount of large energy minority carriers are placed in the conduction band in a p-type semiconductor. A monoatomic layer of cesium and oxygen is positioned on the positively biased contact. This places a negative electron affinity surface layer on the device. The electrons in the conduction band then have enough energy to impel electrons into a vacuum.
Inventors
- 👤 Arno K Hagenlocher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:55
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/30; H01J1/308
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
171 words
A cold cathode electron emitter using double injection spacecharge limited current, comprising: a single semiconductor body, said single body consisting of a homogeneous P-type wide bandgap material; first and second conductor plates mounted on opposite sides of said single semiconductor body, said second plate being formed with an aperture defining an electron emitting surface of said single semiconductor body; a thin layer of work function reducing material coated on said electron emitting surface; bias voltage means connected across said plates, said voltage at said second plate being more positive than said voltage at said first plate; and said single semiconductor body having a thickness measured between said plates, a lifetime and a thermal carrier concentration and said bias means having a magnitude such that said single semiconductor body and said means produce double injection space-charge limited current within said single semiconductor body in which electrons are injected from said first plate and holes are injected from said second plate to excite electrons into the conduction band of said single semiconductor body.
Claim 2
Dependent Claim
171 words
A cold cathode electron emitter using double injection spacecharge limited current, comprising: a single semiconductor body, said single body consisting of a homogeneous P-type wide bandgap material; first and second conductor plates mounted on opposite sides of said single semiconductor body, said second plate being formed with an aperture defining an electron emitting surface of said single semiconductor body; a thin layer of work function reducing material coated on said electron emitting surface; bias voltage means connected across said plates, said voltage at said second plate being more positive than said voltage at said first plate; and said single semiconductor body having a thickness measured between said plates, a lifetime and a thermal carrier concentration and said bias means having a magnitude such that said single semiconductor body and said means produce double injection space-charge limited current within said single semiconductor body in which electrons are injected from said first plate and holes are injected from said second plate to excite electrons into the conduction band of said single semiconductor body.
Claim 3
Dependent Claim
24 words
The emitter defined in claim 1, wherein said work function reducing material comprises a material selected from the group consisting of cesium and oxygen.
Claim 4
Dependent Claim
14 words
The emitter defined in claim 1 wherein said single semiconductor body is gallium phosphide.
Claim 5
Dependent Claim
21 words
The emitter defined in claim 1 wherein said bias voltage means includes biasing said single semiconductor body at about 80 volts.
Claim 6
Dependent Claim
20 words
The emitter defined in claim 1 wherein said single semiconductor body has a lifetime greater than about 10 4 seconds.
Claim 7
Dependent Claim
20 words
The emitter defined in claim 1 wherein said single semiconductor body has a sample thickness less than about 2 mils.
Claim 8
Dependent Claim
25 words
The emitter defined in claim 1 wherein said single semiconductor body has a thermal carrier concentration of between 1013 to 1015 atoms per cubic centimeter.
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) | 1978-03-17 | 1978-09-16 | 1979-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-17 | 1982-09-16 | 1983-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-17 | 1986-09-16 | 1987-03-18 | $7700.00 | Window Closed / Lapsed |