Imaging device

An imaging device comprising:

• a circuit comprising a first region and a second region;
• a first transistor over the first region;
• a first photoelectric conversion element over the first transistor, the first photoelectric conversion element comprising a first photoelectric conversion layer;
• a second transistor over the second region;
• and
• a second photoelectric conversion element over the second transistor, the second photoelectric conversion element comprising the first photoelectric conversion layer,
• wherein each of the first transistor and the second transistor comprises an oxide semiconductor in a channel formation region,
• wherein the first transistor is electrically connected to the first photoelectric conversion element, and
• wherein the second transistor is electrically connected to the second photoelectric conversion element.

An imaging device comprising:

• a circuit comprising a first region and a second region;
• a first transistor over the first region;
• a first photoelectric conversion element over the first transistor, the first photoelectric conversion element comprising a first photoelectric conversion layer;
• a second transistor over the second region;
• and
• a second photoelectric conversion element over the second transistor, the second photoelectric conversion element comprising the first photoelectric conversion layer,
• wherein each of the first transistor and the second transistor comprises an oxide semiconductor in a channel formation region,
• wherein the circuit comprises a third transistor comprising silicon in a channel formation region,
• wherein the first transistor is electrically connected to the third transistor,
• wherein the first transistor is electrically connected to the first photoelectric conversion element, and
• wherein the second transistor is electrically connected to the second photoelectric conversion element.