High-responsivity graphene/hyperdoped-silicon heterostructure infrared photodetectors

Strong sub-bandgap absorption of hyperdoped silicon caused by an impurity deep band has attracted a lot of interest in recent years, which is promising for photodetector application. Currently, the responsivity of hyperdoped Si photoconductors is still low due to the carrier scattering by hyperdoping induced defects, which impedes their application. Here, we prepare a high-responsivity silver hyperdoped silicon heterostructure infrared photoconductor by using graphene as the carrier transport layer. The characterization of the dark I-V curve illustrates that the efficiency of the separation and collection efficiency of carriers of the Si: Ag/Gr photoconductor was obviously improved, compared with the conventional Si: Ag photoconductor. Under a low bias of 0.3 V, the external quantum efficiency (EQE) of the Si: Ag/Gr photoconductor reached 97.26% at 1310 nm and 7.37% at 1550 nm, respectively. These results pave a new way to the hyperdoped silicon heterostructure infrared photodetectors with high responsivity.