Device for operating with THz and/or IR and/or MW radiation

Patent metadata

Field	Value
Publication number	US-11444218-B2
Application number	US-201816957045-A
Country	US
Kind code	B2
Filing date	Dec 24, 2018
Priority date	Dec 22, 2017
Publication date	Sep 13, 2022
Grant date	Sep 13, 2022

Abstract

The present invention relates to a device for operating with THz and/or IR and/or MW radiation, comprising: —an antenna having one or more antenna branches (A 1 ; A 1 , A 2 ) and adapted to operate in the THz and/or IR and/or MW frequency range; and —a structure made of at least one photoactive material defining a photo-active area (Ga) arranged to absorb light radiation impinging thereon. The focus area of the at least one antenna branch (A 1 ; A 1 , A 2 ) is dimensionally equal or smaller than the photo-active area (Ga).

First claim

The invention claimed is:

1. A device for operating with at least one of THz, IR, and MW radiation, comprising:
an antenna having at least one antenna branch and adapted to operate in at least one of a THz, IR, and MW frequency range; and
a structure made of at least one photoactive material defining a photo-active area arranged to absorb light radiation impinging thereon;
wherein said at least one antenna branch has a focus area which is dimensionally equal or smaller than said photo-active area,
wherein said at least one photoactive material of said structure has a high Seebeck coefficient and comprises two sections with different Seebeck coefficients, such that said photo-active area, within an active channel having a Seebeck gradient and arranged to absorb light radiation impinging thereon, is defined at an interface between said two sections and through adjacent regions thereof at both sides of the interface, and wherein said focus area is dimensionally equal or smaller, according to a first direction, than the dimension of the photo-active area measured in parallel to said first direction and transversally to said interface across said adjacent regions,
and wherein the device is optimized for a photoresponse based on a photo-thermal effect, where a photoresponse is generated through light-induced charge carrier heating, in combination with the presence of said Seebeck gradient.

2. The device according to claim 1 , wherein said photo-thermal effect is a photo-thermoelectric effect.

3. The device according to claim 2 , wherein said dimension of the photo-active area measured in parallel to said first direction and transversally to said interface across said adjacent regions is 2L cool , where L cool is the cooling length of hot carriers on both adjacent regions.

4. The device according to claim 2 , wherein another dimension of the photo-active area is defined by a width of the structure made of the at least one photoactive material.

5. The device according to claim 2 , wherein said antenna has at least two antenna branches that are separated by a distance, measured along a separation direction, which is equal or smaller than the dimension of said photo-active area measured along a direction that is parallel to said separation direction.

6. The device according to claim 2 , further comprising a split-gate comprising first and second gate sections separated by a gap and capacitively coupled to said structure to create said two sections when a voltage differential is applied to the split-gate, wherein at least one of said focus area of the at least one antenna branch and said distance separating said at least two antenna branches is dimensionally equal or smaller than a separation distance defined by said gap separating the first and second gate sections and being measured along a direction that is parallel to at least one of said first direction and said separation direction.

7. The device according to claim 6 , wherein said antenna has at least two antenna branches that are separated by a distance, measured along a separation direction, which is equal or smaller than the dimension of said photo-active area measured along a direction that is parallel to said separation direction, and wherein said antenna and said split-gate are the same element, each of said at least two antenna branches being a respective of said first and second gate sections.

8. The device according to claim 2 , further comprising a bottom dielectric layer and an active layer made of said at least one photoactive material arranged on top of said bottom dielectric layer.

9. The device according to claim 8 , further comprising a top dielectric layer, wherein said active layer is arranged between said top and said bottom dielectric layers.

10. The device according to claim 9 , wherein said structure comprises an encapsulated graphene structure having, as said active layer, at least a graphene layer arranged between said top and said bottom dielectric layers.

11. The device according to claim 10 , further comprising a mechanism for enhancing the photoresponse of the device, by exploiting graphene plasmons of the graphene layer.

12. The device according to claim 8 , wherein said antenna has at least two antenna branches that are separated by a distance, measured along a separation direction, which is equal or smaller than the dimension of said photo-active area measured along a direction that is parallel to said separation direction, and wherein said bottom dielectric layer is arranged over the antenna bridging a gap between the two antenna branches so that said interface between the two sections of the structure is arranged over said antenna branches gap.

13. The device according to claim 2 , further comprising one or more active layers made of at least one of the following photoactive materials: graphene, black phosphorus, Bi 2 Te 3 , Bi 2 Te 2 Se, or (Bi,Sb) 2 (Te,Se) 3 .

14. The device according to claim 2 , constituting a detector of said at least one of THz, IR, and MW radiation, wherein the antenna is configured and arranged to focus and confine said at least one of THz, IR, and MW radiation in the focus area of the at least one antenna branch, to concentrate said at least one of THz, IR, and MW radiation at said photo-active area, which is arranged to absorb said at least one of THz, IR, and MW radiation, and the device further comprises at least first and second electrical contacts electrically connected to distanced regions of the structure to measure photo-induced current flowing between said first and second electrical contacts, through the structure, when said at least one of THz, IR, and MW radiation impinges on the photo-active area.

15. The device according to claim 2 , constituting an emitter of said at least one of THz, IR, and MW radiation, wherein said photo-active area is arranged to absorb light radiation from femtosecond light pulses shined thereon, wherein the device further comprises a controlled light source adapted and arranged to generate and emit controlled femtosecond light pulses on said photo-active area, so that a photothermoelectrically induced local photovoltage is created at the structure by ultrafast charge separation which leads to the generation of said at least one of THz, IR, and MW radiation, and wherein the antenna is configured and arranged to emit said generated at least one THz, IR, and MW radiation to far field regions around the device.

16. The device according to claim 15 , further comprising:
a split-gate comprising first and second gate sections separated by a gap and capacitively coupled to said structure to create said two sections when a voltage differential is applied to the split-gate, wherein at least one of said focus area of the at least one antenna branch and said distance separating said at least two antenna branches is dimensionally equal or smaller than a separation distance defined by said gap separating the first and second gate sections and being measured along a direction that is parallel to at least one of said first direction and said separation direction; and
a first voltage source connected to the first gate section and a second voltage source connected to the second gate section, to generate and apply said voltage differential to the split-gate;

wherein the first and second voltage sources are adapted to generate and apply said voltage differential to the split-gate to electrostatically control the generation and emission of said at least one THz, IR, and MW radiation.

17. The device according to claim 2 , wherein the device is configured and

Assignees

• Fundacio Inst De Ciencies Fotòniques
• Inst Catalana Recerca Estudis Avancats
• Asociacion Centro De Investig Cooperativa En Nanociencias Cic Nanogune
• Fundacio Inst De Ciencies Fotoniques

Inventors

• Tielrooij Klaas-Jan
• Koppens Frank
• Hillenbrand Rainer
• Autore Marta

Classifications

• Y02E10/547

  Monocrystalline silicon PV cells · CPC title

• H01L31/028

  Electricity · mapped topic

• H01L31/02002

  Electricity · mapped topic

• H01L31/09

  Electricity · mapped topic

• H01L31/113 Primary

  Electricity · mapped topic