Fig. 1. （a）The schematic diagram of In_0.81Ga_0.19As/In_0.81Al_0.19As detector structure，（b）the schematic diagram of In_0.53Ga_0.47As/InP detector structure

Fig. 2. （a）The SCM images of InGaAs/InAlAs detectors with three different diffusion depths，（b）the photocurrent response of the device with impurity diffusion in the InAlAs capping layer or into the InGaAs absorption layer

Fig. 3. （a）The SCM image of InGaAs/InP P-i-N detector structure，（b）the SCM curve across S1，（c）the SCM curve across S2

Fig. 4. The SCM image of photosensitive elements with connected defects due to the lateral diffusion in InGaAs/InP P-i-N detector