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US4686556A
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Photocathode for the infra-red range
Assignee: Individual
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Filing: 1985-11-13
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Granted: 1987-08-11
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Expires: 2005-11-13
Abstract
Abstract The invention relates to a photocathode for the infra-red range having a plurality of layers of semi-conductive and conductive material. The photocathode is transparent and sensitive in a spectral range of between approx. 1 and 20 μm. This is achieved by the following layer structure: p 1 : a highly doped p-layer n 2 : a highly doped n-layer i 3 : an intrinsic layer p 4 : a highly doped p-layer m 5 : a thin metal layer, preferably of an atomic layer of Cs. The spectral sensitivity can be adjusted by applying a negative bias voltage to the layer p 1 with respect to the layer P 4 . When this happens, the Fermi level of the layer p 2 is shifted and the work function of the electrons is reduced.
Inventors
- 👤 Klaus Dietrich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:34
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: 9
Claim 1
Independent Claim
92 words
Photocathode for the infrared range, comprising a plurality of layers of semiconductive and conductive materials, forming a layer structure in which adjacent layers are arranged in the order of a first, highly doped p-layer, a second, highly doped n-layer, a third, intrinsic layer, a fourth, highly doped p-layer, and a fifth, thin metal layer having a thickness of about an atomic layer of Cs, the first, second and fourth layers be biased by predetermined voltages, and wherein the term highly-doped means a carrier concentration of at least 10 18 cm -3 .
Claim 2
Dependent Claim
92 words
Photocathode for the infrared range, comprising a plurality of layers of semiconductive and conductive materials, forming a layer structure in which adjacent layers are arranged in the order of a first, highly doped p-layer, a second, highly doped n-layer, a third, intrinsic layer, a fourth, highly doped p-layer, and a fifth, thin metal layer having a thickness of about an atomic layer of Cs, the first, second and fourth layers be biased by predetermined voltages, and wherein the term highly-doped means a carrier concentration of at least 10 18 cm -3 .
Claim 3
Dependent Claim
92 words
Photocathode for the infrared range, comprising a plurality of layers of semiconductive and conductive materials forming a layer structure, in which adjacent layer are arranged in the order of a first, reflecting metal electrode, a second, highly doped n-layer, a third, intrinsic layer, a fourth, highly doped n-layer, and a fifth, thin metal layer having a thickness of about an atomic layer of Cs, the first, second and fourth layers be biased by predetermined voltages, and wherein the term highly-doped means a carrier concentration of at least 10 18 cm -3 .
Claim 4
Dependent Claim
92 words
Photocathode for the infrared range, comprising a plurality of layers of semiconductive and conductive materials forming a layer structure, in which adjacent layer are arranged in the order of a first, reflecting metal electrode, a second, highly doped n-layer, a third, intrinsic layer, a fourth, highly doped n-layer, and a fifth, thin metal layer having a thickness of about an atomic layer of Cs, the first, second and fourth layers be biased by predetermined voltages, and wherein the term highly-doped means a carrier concentration of at least 10 18 cm -3 .
Claim 5
Dependent Claim
56 words
Photocathode according to claim 1, wherein the layers p 1 , n 2 and p 4 are biased by different voltages, the voltage at p 4 defining the potential of the photocathode whereas at p 1 the voltage U 1 and at n 2 the voltage U 2 is controlling the spectral characteristics of the photocathode.
Claim 6
Dependent Claim
18 words
Photocathode according to claim 3, wherein a mirror layer S is deposited on the layer p 1 .
Claim 7
Dependent Claim
42 words
Photocathode according to claim 2, wherein the layers RE and p 4 are biased by different voltages, the voltage at p 4 defining the potential of the photocathode while at RE the voltage U 2 controls the spectral characteristics of the photocathode.
Claim 8
Dependent Claim
65 words
Photocathode according to claim 1 or 2, wherein the carrier concentration from layer p 1 to layer n 2 changes abruptly from a high p-doping to a high n-doping with tunnel diode properties and wherein the thickness of the layer p 1 is between 1 and 100 μm, while said high doping corresponds to a carrier concentration of at least 10 18 cm -3 .
Claim 9
Dependent Claim
21 words
Photocathode according to claim 1 or 2, wherein the thickness of the layer p 4 lies between 10 and 50 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) | 1990-08-10 | 1991-02-09 | 1991-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-10 | 1995-02-09 | 1995-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-10 | 1999-02-09 | 1999-08-11 | $7700.00 | Window Closed / Lapsed |