Vertically stacked light sensors

A semiconductor structure, comprising:

• a first substrate comprising a first semiconductor material;
• a first interconnect structure disposed on a front-side surface of the first substrate;
• a first light sensor disposed within the first substrate, wherein the first light sensor is configured to absorb electromagnetic radiation within a first wavelength range;
• a second substrate underlying the first substrate;
• a second interconnect structure disposed on a front-side surface of the second substrate, wherein the first interconnect structure is disposed on and electrically coupled to the second interconnect structure;
• and
• a second light sensor disposed within an absorption structure, wherein the absorption structure is disposed within or on the second substrate, wherein the second light sensor is configured to absorb electromagnetic radiation within a second wavelength range different from the first wavelength range, wherein the absorption structure underlies the first light sensor and comprises a second semiconductor material different from the first semiconductor material.