A sensor includes a first electrode, a second electrode facing the first electrode, and a light absorbing layer between the first electrode and the second electrode. The light absorbing layer may have a first absorption spectrum having a first absorption peak in a first infrared wavelength region and a second absorption peak in a second infrared wavelength region, the second infrared wavelength region being a longer wavelength region than the first infrared wavelength region. The second absorption spectrum does not at least partially overlap with the first absorption spectrum. The second absorption spectrum may have a lower absorption intensity than the first absorption spectrum. An external quantum efficiency (EQE) spectrum that is amplified in the second infrared wavelength region is exhibited in the sensor.