Improved optical response of superlattice graded InAlAs/InGaAs p-i-n photodetectors

A number of important optoelectronic device utilize the InAlGaAs/InP materi al system. The reduction of carrier trapping at the In0.53Ga0.47As/In0.52Al 0.48As heterointerface is advantageous towards improving both the quantum e fficiency and frequency response of devices utilizing InGaAs active regions . Direct current and transient optical response characteristics were measur ed for p-i-n double-heterojunction photodiodes utilizing either abrupt or s uperlattice (SL) graded heterointerfaces. SL graded devices showed improved collection efficiency at electric fields <3 kV/cm and faster temporal resp onse at electric field <70 kV/cm as compared to identical devices having ab rupt interfaces. (C) 1998 American Institute of Physics. [S0003-6951(98)016 49-0].