US3868523A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semitransparent photocathode
Assignee: US Philips Corp
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Filing: 1973-11-05
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Granted: 1975-02-25
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Expires: 1993-11-05
Abstract
Abstract In order to obtain an optimum freedom in the choice of the material in a semitransparent photocathode which consists of IIIV semiconductor compounds and in which the matching of the lattice constant of the active layer to that of the substrate is achieved by an intermediate layer, and thus to arrive at a sensitivity and/or optical wide band condition which is as high as possible, according to the invention the composition of the intermediate layer is independent of the substrate and of the active layer and its lattice constant differs from the lattice constant of the active layer by less than 0.3% and differs from the grid constant of the substrate up to several per cent, for example up to 3%. Such a photocathode may consist in particular of a substrate of GaP, an intermediate layer of AlxGa1 xAs with x>0.8 and an active layer of GaAs.
Inventors
- 👤 Anton Martin Klopfer
- 👤 Siegfried Garbe
- 👤 Gunter Frank
- 👤 Manfred Peterek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 04:25
CPC Classifications
C; C30; C30B; C30B19/00; C30B19/12; H; H01; H01J; H01J1/00; H01J1/02; H01J1/34; H01J2201/00; H01J2201/34; H01J2201/342; H01J2201/3421; H01J2201/3423
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
65 words
A SEMITRASPERENT PHOTOCATHODE OF III-V SEMICONDUCTOR COMPOUNDS, HAVING A SUBSTRATE, AN INTERMEDIATE LAYER AND AN ACTIVE LAYER, THE ENERGY GAP OF THE ACTIVE LAYER BEING SMALLER THAN THAT OF THE INTERMEDIATE LAYER AND THE ACTIVE AND THE INTERMEDIATE LAYER BEING P-DOPED, THE INTERMEDIATE LAYER HAVING A COMPOSITION HAVING ELEMENTS WHICH DIFFER FROM THOSE OF THE SUBSTRATE AND THE ACTIVE LAYER AND A LATTICE CONSTANT DIFFER-
Claim 2
Dependent Claim
65 words
A SEMITRASPERENT PHOTOCATHODE OF III-V SEMICONDUCTOR COMPOUNDS, HAVING A SUBSTRATE, AN INTERMEDIATE LAYER AND AN ACTIVE LAYER, THE ENERGY GAP OF THE ACTIVE LAYER BEING SMALLER THAN THAT OF THE INTERMEDIATE LAYER AND THE ACTIVE AND THE INTERMEDIATE LAYER BEING P-DOPED, THE INTERMEDIATE LAYER HAVING A COMPOSITION HAVING ELEMENTS WHICH DIFFER FROM THOSE OF THE SUBSTRATE AND THE ACTIVE LAYER AND A LATTICE CONSTANT DIFFER-
Claim 3
Dependent Claim
15 words
A photocathode as claimed in claim 1, wherein the intermediate layer consists of AlxGa1 xAs.
Claim 4
Dependent Claim
15 words
A photocathode as claimed in claim 1, wherein the intermediate layer consists of InxGa1 xP.
Claim 5
Dependent Claim
15 words
A photocathode as claimed in claim 1, wherein the intermediate layer consists of AlxIn1 xAs.
Claim 6
Dependent Claim
16 words
A photocathode as claimed in claim 1, wherein the intermediate layer consists of AlxGayIn1 x yP.
Claim 7
Dependent Claim
13 words
a photocathode as claimed in claim 1, wherein the substrate consists of GaP.
Claim 8
Dependent Claim
13 words
A photocathode as claimed in claim 1, wherein the substrate consists of sapphire.
Claim 9
Dependent Claim
13 words
A photocathode as claimed in claim 1, wherein the substrate consists of spinel.
Claim 10
Dependent Claim
14 words
A photocathode as claimed in claim 8, wherein the substrate consists of Mg-Ga spinel.
Claim 11
Dependent Claim
20 words
A photocathode as claimed in claim 9, wherein the substrate consists of a mixed spinel system such as Mg(InxGa1 x)2O4.
Claim 12
Dependent Claim
29 words
A photocathode as claimed in claim 1, wherein the active layer consists of a material selected from the group consisting of GaAs, (Ga, In) As and In (As, P).
Claim 13
Dependent Claim
31 words
A photocathode as claimed in claim 1, wherein the substrate consists of GaP, the intermediate layer consists of AlxGa1 xAs with x > 0.8 and the active layer consists of GaAs.
Claim 14
Dependent Claim
39 words
A photocathode as claimed in claim 1, wherein the substrate is a frame, consists of the same material as the active layer, and the intermediate layer and the active layer in the operative part of the photocathode are self-supporting.
Claim 15
Dependent Claim
26 words
A photocathode as claimed in claim 1, wherein the substrate consists of sapphire, the intermediate layer consists of AlAs, and the active layer consists of GaAs.
Claim 16
Dependent Claim
32 words
A photocathode as claimed in claim 1, wherein the substrate consists of a spinel, the intermediate layer consists of AlxGa1 xAs with x > 0.8, and the active layer consists of GaAs.
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) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |