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Avalanche photodetector including means for separating electrons and holes

Patent ·
OSTI ID:5769461
The invention is a reduced noise avalanche photodetector in which the energy band structure causes one type of charge carrier to ionize at a faster rate than the other type of charge carrier. In a preferred embodiment the inventive structure comprises a relatively narrow bandgap semiconductor layer of a first conductivity type located contiguous with and between two relatively wider bandgap layers of a second conductivity type. Means are provided for applying an electric field parallel to the plane of the layers. In a preferred mode of operation, light is absorbed in the narrow bandgap layer and charge carriers are generated in response thereto. One type of charge carrier is confined to the narrow bandgap layer and undergoes avalanche multiplication therein in a direction parallel to the applied field. The other type of charge carrier is swept out into the wider bandgap layers where avalanche multiplication takes place at a negligible rate.
Assignee:
AT and T Bell Laboratories
Patent Number(s):
US 4486765
OSTI ID:
5769461
Country of Publication:
United States
Language:
English