Patent ID: 8723161

Claim:
A two-color detector comprising: a first absorber layer exhibiting a first valence band energy characterized by a first valence band energy function, said first absorber layer comprising a group III-V quaternary alloy; a barrier layer exhibiting a second valence band energy characterized by a second valence band energy function, the barrier layer adjoining the first absorber layer at a first interface; and a second absorber layer exhibiting a third valence band energy characterized by a third valence band energy function, the barrier layer adjoining the second absorber layer at a second interface such that the barrier layer is between the first and second absorber layers, said second absorber layer comprising a group III-V quaternary alloy; wherein the first and second valence band energy functions are substantially functionally or physically continuous at the first interface and the second and third valence band energy functions are substantially functionally or physically continuous at the second interface.