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US 6,271,537 B1Granted
Slotted quantum well sensor
AssigneeCalifornia Institute of Technology
InventorsSarath D. Gunapala, Sumith V. Bandara, John K. Liu, Daniel W. Wilson
Life of this patent
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Abstract
Quantum-well sensors having an array of spatially separated quantum-well columns formed on a substrate. A grating can be formed increase the coupling efficiency.
Claims13
A quantum-well semiconductor device that senses radiation energy, comprising:
- a substrate of a substantially transparent semiconductor material to receive the radiation energy;
- a plurality of quantum-well structures formed over said substrate, arranged in columnar shapes and spatially separated from one another by a gap to form an optical grating that diffracts the radiation energy said gap being electrically insulating, and
- a plurality of separate metallic elements respectively formed over said quantum-well structures to enhance a diffraction efficiency of said optical grating,
- wherein each quantum-well structure includes, a first conductive contact layer formed over said substrate, a quantum-well stack having a plurality of alternating quantum-well layers formed in parallel over said first conductive contact layer and operating to absorb radiation polarized perpendicularly to said quantum-well layers, and a second conductive contact layer formed over said quantum-well stack, and
- wherein said gap between two adjacent quantum-well structures is configured to spatially separate and electrically insulate each layer of one quantum-well structure from each layer of another quantum-well structure.
2 more elements
A quantum-well semiconductor device that senses radiation energy, comprising:
- a substrate of a substantially transparent semiconductor material;
- and
- a plurality of quantum-well columns spatially separated from one another by an electrically-insulating gap and formed over said substrate to form a periodic array that diffracts the radiation energy,
- wherein each quantum-well column includes, a first conductive contact layer formed over said substrate, a quantum-well stack having a plurality of alternating quantum-well layers parallel formed over said first conductive contact layer and operating to absorb radiation by at least one intraband transition, and a second conductive contact layer formed over said quantum-well stack, and said gap between two adjacent quantum-well columns is configured to spatially separate and electrically insulate each layer of one quantum-well column from each layer of another quantum-well column, and
- wherein dimensions and indices of said plurality of quantum-well columns and said gap are configured to make each quantum-well column an optical cavity in a resonance condition so that a magnitude of received radiation having a polarization perpendicular to said quantum-well layers is greater than a magnitude of received radiation having a polarization perpendicular to said quantum-well layers when the resonance condition is not met.
2 more elements
A method for detecting radiation by using a quantum-well structure that absorbs radiation by an intraband transition, comprising:
- providing a plurality of quantum-well columns spatially separated from one another by an electrically-insulating gap and formed over a transparent substrate to form a periodic array, wherein each quantum-well column includes a plurality of alternating quantum-well layers formed between two opposing conductive contact layers;
- configuring said gap between two adjacent quantum-well columns to spatially separate and electrically insulate each layer of one quantum-well column from each layer of another quantum-well column;
- configuring dimensions of said quantum-well columns and said gap to form an optical grating and to diffract the radiation energy;
- placing a plurality of identical, separate grating teeth respectively on said quantum-well columns to enhance a diffraction efficiency of said optical grating;
- and
- directing an incident radiation beam into each quantum-well column through the substrate to produce radiation polarization perpendicular to said quantum-well layers.
3 more elements
Dependencies are inferred from the claim text.