Interface Engineering to Enhance Photoresponse of Core-Shell Silicon Nanowire Photodetectors

We report a core-shell silicon nanowire photodetector with enhanced responsivity. The interface trap plays critical role to determine the performance of core-shell photodetector. The effect of interface quality on the photoresponse is investigated using crystalline silicon and polysilicon shells. The device with single-crystalline silicon shell exhibits higher responsivity than that with polysilicon shell. The performance degradation of polysilicon device is caused by the grain boundary, which is source and sink for defects. Based on these results, the single-crystalline silicon shell was used for fabricating core-shell silicon nanowire photodetector. The photodetector exhibits the maximum responsivity of 0.51 A/W, which is 10% higher than the planar photodetector. These results here suggest that the core-shell homogeneous silicon nanowire structure can be promising component for photodetector application.1