Patent ID: 7129489

Claim:
A detector of incident radiation in the infrared region comprising: at least one detector unit cell; and a common contact and a contact bump coupled to the at least one unit cell for imposing a bias condition across the unit cell; wherein the unit cell comprises: a first absorption layer for outputting one of a n-type or a p-type charge carrier current that is proportional to absorption of energy in a first band when a bias in a first direction is imposed across the unit cell; a second absorption layer for outputting the other of a n-type or a p-type charge carrier current that is proportional to absorption of energy in a second band when a bias in the first direction is imposed across the unit cell; and a barrier layer disposed between the first and second absorption layers that allows photocurrent from the first absorption layer to flow when said bias in the first direction is below a threshold voltage and that allows photocurrent from both the first and second absorption layers to flow when said bias in the first direction exceeds the threshold voltage.