Image sensors including semiconductor channel patterns

1. An image sensor comprising:

a substrate including a floating diffusion region and a pixel circuit;

an interlayer insulating layer on the substrate;

a contact node and a first electrode on the interlayer insulating layer;

a dielectric layer on a top surface of the first electrode;

a channel semiconductor pattern on the dielectric layer and connected to the contact node; and

a photoelectric conversion layer on the channel semiconductor pattern,

wherein the channel semiconductor pattern includes a semiconductor material having an electron mobility that is higher than an electron mobility of the photoelectric conversion layer; and

wherein the image sensor further comprises an isolation insulating pattern on the dielectric layer, wherein the isolation insulating pattern is in contact with sidewalls of the channel semiconductor pattern and surrounds the channel semiconductor pattern when viewed from a plan view.

2. The image sensor of claim 1 , wherein a conduction band energy level of the channel semiconductor pattern is lower than a conduction band energy level of the photoelectric conversion layer, and

wherein a valence band energy level of the channel semiconductor pattern is lower than a valence band energy level of the photoelectric conversion layer.

3. The image sensor of claim 2 , wherein the channel semiconductor pattern includes at least one of InGaZnO, ZnO, SnO 2 , CdSe, CdS, or MoS 2 .

4. The image sensor of claim 1 , further comprising:

a via-plug disposed in the interlayer insulating layer;

wherein the via-plug electrically connects the floating diffusion region to the contact node.

5. The image sensor of claim 1 , wherein the photoelectric conversion layer includes an electron donating organic material and an electron accepting organic material, and

wherein the organic materials comprise a bulk hetero junction-type PN junction structure.

6. The image sensor of claim 1 , wherein the contact node overlaps with a central portion of the channel semiconductor pattern, and

wherein the first electrode surrounds an entire periphery of the contact node.

7. The image sensor of claim 1 , wherein the contact node is adjacent to one edge of the channel semiconductor pattern or a corner between adjacent edges of the channel semiconductor pattern when viewed from a plan view, and

wherein the first electrode surrounds a portion of a periphery of the contact node when viewed from a plan view.

8. The image sensor of claim 1 , further comprising:

an isolation insulating pattern disposed on the interlayer insulating layer,

wherein the isolation insulating pattern is in contact with sidewalls of the dielectric layer and sidewalls of the channel semiconductor pattern and surrounds the dielectric layer and the channel semiconductor pattern when viewed from a plan view.

9. The image sensor of claim 1 , further comprising:

a guard electrode disposed on the interlayer insulating layer,

wherein the guard electrode surrounds the contact node and the first electrode when viewed from a plan view, and

wherein the dielectric layer extends between the contact node and the first electrode and between the first electrode and the guard electrode.