| Abstract: | In a superlattice (SL) photodetector, each period of the SL includes
first and second semiconductor layers having different compositions, at
least one of which comprises indium arsenide (InAs). At least one of
these two semiconductor layers has a graded composition. In embodiments,
the first semiconductor layer comprises InAs and the second semiconductor
layer is a graded layer comprising indium arsenide antimonide (InAsSb),
wherein the antimony (Sb) concentration is varied. In examples, the Sb
concentration in the second layer gradually increases from the top and
bottom toward the middle of the layer. |