The inventive concepts relate to image sensors. The image sensor includes 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. The channel semiconductor pattern includes a semiconductor material having an electron mobility that is higher than an electron mobility of the photoelectric conversion layer.