Method of forming group iii-v compound photoemitters having a high quantum efficiency and long wavelength response
Abstract
Abstract A PHOTOEMITTER HAVING A HIGH QUANTUM EFFICIENCY AND A LOW WORK FUNCTION FOR PHOTOEMISSION, E.G. PHOTOELECTRIC THRESHOLD, IS FORMED BY DEPOSITING A 10-100 A. FILM OF A WIDE BANDGAP GROUP III-V COMPOUND, E.G. GALLIUM PHOSPHIDE, ATOP A 0.5-10 MICRON THICK LAYER OF A SECOND GROUP III-V COMPOUND, E.G. GALLIUM ANTIMONIDE, HAVING A BANDGAP MATCHING THE DESIRED PHOTOELECTRIC THRESHOLD. THE FILM SURFACE THEN IS TREATED WITH CESIUM (OR CESIUM AND OXYGEN) TO REDUCE THE SURFACE WORK FUNCTION OF THE COMPOSITE STRUCTURE TO THE DESIRED PHOTOELECTRIC THRESHOLD. WHEN THE GROUP III-V LAYER FORMING THE PHOTOEMITTER IS EPITAXIALLY GROWN ATOP AN ORIENTED SUBSTRATE OF A SEMICONDUCTIVE MATERIAL SUCH AS GALLIUM ARSENIDE HAVING A BANDGAP WIDER THAN THE BANDGAP OF THE OVERLYING LAYER, THE RESULTING PHOTOEMITTER IS TRANSPARENT ONLY IN A RANGE BETWEEN THE BANDGAP OF THE SUBSTRATE AND THE BANDGAP OF THE OVERLYING LAYER.
Inventors
- 👤 Donald L Schaefer
Bibliographic Details
Claims Analysis
Total Claims: 0References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-27 | 1975-12-27 | 1976-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-27 | 1979-12-27 | 1980-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-27 | 1983-12-27 | 1984-06-27 | $7700.00 | Window Closed / Lapsed |