New type of optoelectronic devices-forward-biased long photodiodes based on graded III-V alloy compounds

We have proposed and demonstrated three new types of injection forward-biased photodiodes with three different mechanisms of the photoresponse spectrum formation in Al_xGa_1-xAs graded p-n structures with (a) grading in the band-gap only, (b) grading in the compensation of the graded band-gap base and (c) Γ-χ intervalley crossover. In structures (a) and (b) the change in the injection-current leads to a special photoresponse transformation from broad-band to exceedingly selective. While the current sensitivity exceeds 10²-10³ A/W. Photoresponse in (c) structures has a double-peaked spectrum. Also it is possible to change the shape of the spectrum