Provided is an image sensor. The image sensor can include a first substrate comprising a pixel portion in which a readout circuitry is provided and a peripheral portion in which a peripheral circuitry is provided. An interlayer dielectric including lines can be formed on the first substrate to connect with the readout circuitry and the peripheral circuitry. A crystalline semiconductor layer can be provided on a portion of the interlayer dielectric corresponding to the pixel portion through a bonding process. The crystalline semiconductor layer can include a first photodiode and second photodiode. The first and second photodiodes can be defined by device isolation trenches in the crystalline semiconductor layer. A device isolation layer can be formed on the crystalline semiconductor layer comprising the device isolation trenches. An upper electrode layer passes through the device isolation layer to connect with a portion of the first photodiode. An expose portion can be formed in the upper electrode layer to selectively expose an upper region of the first photodiode. A passivation layer can be formed on the first substrate on which the expose portion is provided.