Image sensor with non-local readout circuit and optoelectronic device comprising said image sensor

Patent metadata

Field	Value
Publication number	US-9955100-B2
Application number	US-201615227327-A
Country	US
Kind code	B2
Filing date	Aug 3, 2016
Priority date	Aug 3, 2015
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

Provided are image sensors with non-local readout circuits that include a substrate and a plurality of pixels and operatively connected to a control unit, wherein the control unit has first and second biasing circuits for providing, respectively, substantially symmetrical first and second biasing voltages and including, respectively, first and second selection means to selectively bias the pixels; and a readout circuit for reading out the pixels; and in that each pixel includes a photo-active element that has a photosensitizing layer associated to a transport layer; a non-photo-active reference element; first and second contacts circuitally connected, respectively, to the first and second biasing circuits; and an output contact circuitally connected to the readout circuit; wherein the photo-active element is circuitally connected between the first and output contacts, and the reference element is circuitally connected between the output and second contacts. Also provided are optoelectronic systems that include the image sensor.

First claim

What is claimed is:

1. An image sensor with non-local readout circuit, comprising a substrate, a plurality of pixels arranged on a first area of the substrate, and a control unit operatively connected to the plurality of pixels and adapted to selectively bias said plurality of pixels and read them out, wherein the control unit comprises:
a first biasing circuit for providing a first biasing voltage;
a second biasing circuit for providing a second biasing voltage, the second biasing voltage being substantially symmetrical to the first biasing voltage with respect to a voltage reference; and
a non-local readout circuit for reading out a photo-signal generated by light impinging on the plurality of pixels;
wherein the first biasing circuit and the second biasing circuit comprise, respectively, first selection means and second selection means to selectively bias one or more pixels of said plurality of pixels that are to be read out at a given time, the first selection means and the second selection means being arranged outside the first area of the substrate;
and wherein each pixel of the plurality of pixels comprises:
a photo-active element comprising a photosensitizing layer associated to a transport layer, the transport layer including at least one layer of a two-dimensional material;
a non-photo-active reference element disposed proximate to the photo-active active element, the non-photo-active reference element having a dark conductance that substantially matches a dark conductance of the photo-active element;
a first contact circuitally connected to the first biasing circuit;
a second contact circuitally connected to the second biasing circuit; and
an output contact circuitally connected to the non-local readout circuit;
wherein the photo-active element is circuitally connected between the first contact and the output contact, and the non-photoactive reference element is circuitally connected between the output contact and the second contact.

2. The image sensor of claim 1 , wherein the non-local readout circuit is arranged outside the first area of the substrate.

3. The image sensor of claim 2 , wherein all pixels of said plurality of pixels are absent of embedded readout electronics.

4. The image sensor of claim 1 , wherein said substantial symmetrical first and second biasing voltages have opposite signs with respect said voltage reference and a magnitude of one differs from a magnitude of the other in less than a 25%.

5. The image sensor of claim 1 , wherein the first biasing circuit and the second biasing circuit are independent biasing circuits having their own independent control electronics providing the first biasing voltage and the second biasing voltage, respectively.

6. The image sensor of claim 1 , wherein the non-photo-active reference element of at least one pixel of the plurality of pixels comprises a transport layer, said transport layer of the non-photo-active reference element including at least one layer of a two-dimensional material.

7. The image sensor of claim 6 , wherein the non-photo-active reference element of said at least one pixel further comprises a photosensitizing layer associated to the transport layer of the non-photo-active reference element.

8. The image sensor of claim 7 , wherein the non-photo-active reference element of said at least one pixel further comprises a first light-blocking layer disposed above the photosensitizing layer and the transport layer of said non-photo-active reference element.

9. The image sensor of claim 8 , wherein the non-photo-active reference element of said at least one pixel further comprises a second light-blocking layer disposed below the photosensitizing layer and the transport layer of said non-photo-active reference element.

10. The image sensor of claim 6 , wherein, for said at least one pixel, the transport layer of the non-photo-active reference element has a smaller area than the transport layer of the photo-active element.

11. The image sensor according to claim 10 , wherein, for said at least one pixel, the transport layer of the non-photo-active reference element has the same shape as a transport layer of the photo-active element.

12. The image sensor of claim 1 , wherein the non-photo-active reference element of at least one pixel of the plurality of pixels is arranged between the substrate and the photo-active element of said at least one pixel.

13. The image sensor of claim 1 , further comprising one or more primary insulating layers associated to the photo-active element of the plurality of pixels.

14. The image sensor of claim 13 , wherein at least one pixel of the plurality of pixels comprises:
a back-gate contact disposed between the substrate and the photo-active element of said at least one pixel, between a primary insulating layer and the substrate, wherein said primary insulating layer is disposed between said photo-active element and the substrate; and/or
a top-gate contact disposed above the photo-active element of said at least one pixel.

15. The image sensor according to claim 6 , further comprising one or more secondary insulating layers associated to the non-photo-active reference element of the plurality of pixels.

16. The image sensor of claim 15 , wherein at least one pixel of the plurality of pixels comprises:
a back-gate contact disposed between the substrate and the non-photo-active reference element of said at least one pixel, between a secondary insulating layer and the substrate, wherein said secondary insulating layer is disposed between said non-photo-active reference element and the substrate; and/or
a top-gate contact disposed above the non-photo-active reference element of said at least one pixel.

17. The image sensor of claim 1 , wherein the plurality of pixels are grouped into clusters, each cluster comprising one or more pixels; and wherein the photosensitizing layer of the photo-active element of the one or more pixels of each cluster is sensitive to a different range of light spectrum.

18. The image sensor of claim 1 , wherein the plurality of pixels are arranged as a two-dimensional array comprising a plurality of rows, each row comprising the same number of pixels; and wherein the first selection means and the second selection means comprise, respectively, first row-select switches and second row-select switches to selectively bias the plurality of rows of the array.

19. The image sensor of claim 18 , wherein the control unit is operatively connected to the first row-select switches and the second row-select switches, and is configured to sequentially read out the plurality of rows by activating the first row-select switch and the second row-select switch of one row at a time.

20. The image sensor of claim 18 , wherein the non-local readout circuit comprises:
a multiplexer comprising as many input terminals as there are pixels in each row and an output terminal, each input terminal of the multiplexer being circuitally connected to the output contact of a pixel of each row; and
an amplifier operatively connected in series to the output terminal of the multiplexer.

21. The image sensor of claim 20 , wherein the non-local readout circuit comprises a storage element configured to store a voltage proportional to the photo-signal generated in a pixel of the plurality of pixels, the storage element being operatively connected in series to the amplifier.

22. The image sensor of claim 18 , wherein the non-local readout circuit comprises as many amplifiers a

Assignees

• Fundacio Inst De Ciencies Fotòniques
• Fundacio Inst De Ciencies Fotòniques

Inventors

• Konstantatos Gerasimos
• Koppens Frank
• Goossens Stijn
• Josépiqueras Juan

Classifications

• H04N25/709 Primary

  Circuitry for control of the power supply · CPC title

• H04N25/76

  Addressed sensors, e.g. MOS or CMOS sensors · CPC title

• H01L27/14614

  Electricity · mapped topic

• H04N5/378 Primary

  Electricity · mapped topic

• H01L27/14623

  Electricity · mapped topic