High performance hyperspectral detectors using photon controlling cavities
View Patent ↗According to various embodiments, a photodetector including a first contact layer, a second contact layer, an active region, and a photonic crystal resonant cavity is disclosed. The photonic crystal resonant cavity can operate as a resonant structure to enhance the response of the photodetector at one or more wavelengths. In various embodiments, the photodetectors including a photonic crystal resonant cavity can, for example, demonstrate increased responsivity and quantum efficiency, lower the operating temperature, and/or be used to form a hyperspectral detector.
1. A photodetector comprising:
a first contact layer;
a second contact layer;
an active region comprising a quantum dot structure and disposed between and is in electrical contact with the first and second contact layers, wherein the quantum dot structure comprises alternating layers of a quantum dot layer and a barrier layer, the quantum dot layer comprising one of GaAs, InAs, InGaAs, AiInAs, InP, and other alloys of AIGaInAsP, and the barrier layer comprising one of AIGaAs and AIGaInP doped to provide carriers for conductivity; and
a photonic crystal resonant cavity disposed between the first and second contact layers, wherein the photonic crystal resonant cavity extends from the first contact layer to the second contact layer through the alternating layers of the quantum dot structure.
2. The photodetector of claim 1 , wherein the photonic crystal resonant cavity comprises of a plurality of localized defects disposed in a portion of the active region and arranged in an array.
3. The photodetector of claim 2 , wherein the plurality of localized defects have a refractive index different than a refractive index of the portion of the active region.
4. The photodetector of claim 2 , wherein the array is a hexagonal pattern.
5. The photodetector of claim 4 , wherein each of the plurality of localized defects comprises a cavity.
6. The photodetector of claim 2 , wherein a ratio of a radii of the localized defects to a lattice constant is between about 0.01 and about 0.5.
7. The photodetector of claim 1 , wherein the active region comprises a quantum well or superlattice structure.
8. The photodetector of claim 7 , wherein the quantum well structure comprises alternating compound semiconductor layers comprising one of AIGaAs, InGaAIAs, InGaAIAsP, and GaAs.
9. The photodetector of claim 1 , wherein the quantum dot structure comprises a dots-in-a-well (DWELL) configuration.
10. A photodetector device comprising:
one or more first contacts
one or more second contacts;
a plurality of active regions, wherein each of the plurality of active regions comprises a quantum dot structure and is in electrical contact with the one or more first contacts and the one or more second contacts, wherein the quantum dot structure comprises alternating layers of a quantum dot layer and a barrier layer, the quantum dot layer comprising one of GaAs, InAs, InGaAs, AiInAs, InP, and other alloys of AIGaInAsP, and the barrier layer comprising one of AIGaAs and AIGaInP doped to provide carriers for conductivity; and
a photonic crystal resonant cavity disposed in each of the plurality of active regions, wherein the photonic crystal resonant cavity extends from at least one of the first contacts to at least one of the second contacts through the alternating layers of the quantum dot structure.
11. The photodetector device of claim 10 , wherein each of the plurality of photonic crystal resonant cavities is tuned to one of a plurality of desired spectral bandwidths.
12. The photodetector device of claim 10 , wherein each of the photonic crystal resonant cavities comprises a plurality of localized defects within a portion of the active region, and wherein the localized defects are dimensioned to tune the photonic resonant cavity to one of the plurality of spectral bandwidths.
13. The photodetector device of claim 11 , wherein the photodetector device is one of a focal plane array, a solar cell, and a diode.
14. A quantum dot infrared photodetector comprising:
a first doped GaAs layer;
a second doped GaAs layer;
a first InAs/InGaAs/GaAs quantum dots-in-a-well structure active region disposed between and is in electrical contact with the first and second doped GaAs layers, wherein the active region includes at least one quantum dot layer, at least one quantum well layer, and at least one barrier layer; and
a photonic crystal resonant cavity disposed in a portion of the active region, wherein the photonic crystal resonant cavity comprises a plurality of localized defects arranged in a desired pattern, the localized defects each extending from the first doped GaAs layer to the second doped GaAs layer through the quantum dot layer, the quantum well layer, and the barrier layer.
15. A hyperspectral focal plane array comprising:
the quantum dot infrared photodetector of claim 14 ; and
one or more additional InAs/InGaAs/GaAs quantum dots-in-a-well structures disposed in an array, wherein each of the one or more additional InAs/InGaAs/GaAs quantum dots-in-a-well structures comprises a photonic crystal resonant cavity, and wherein the localized defects are arranged and sized in each of the photonic crystal resonant cavities to form a tuned multi-band detector.