Antimony‐Doped p‐Type In2Se3 for Heterophase Homojunction with High‐Performance Reconfigurable Broadband Photovoltaic Effect

Abstract Heterophase homojunction (HH) presents a new paradigm in the next‐generation broadband photodetection, light‐emitting diode, and nonvolatile memory devices. Lattice mismatch is one of the fundamental characteristics that makes the HH devices difficult to stand out. In 2 Se 3 , as a polymorphic layered semiconductor, can provide an effective approach to breaking the critical constraint on interlayer lattice mismatch. However, it is extremely important and challenging to control the crystal phase of In 2 Se 3 . In this paper, the phase‐selective growth are achieved by alloying antimony (Sb) into In 2 Se 3 crystal structure forming In 2(1− x ) Sb 2 x Se 3 crystals, where x = 0–20%. Interestingly, for x = 13%, β‐In 1.74 Sb 0.26 Se 3 exhibits a p‐type semiconductor characteristic. Accordingly, an α‐In 2 Se 3 /β‐In 1.74 Sb 0.26 Se 3 van der Waals p–n HH is designed and fabricated. This device not only achieves a broadband spectral photovoltaic response from the visible to near‐infrared (405–1064 nm) but also exhibits a fast photoresponse speed at about microseconds at room temperature. Moreover, the photovoltaic figure‐of‐merits can be greatly modulated by the reconfigurable built‐in potential in the p–n HH that is related to the ferroelectric polarization in α‐In 2 Se 3 . This work enables a great significance of vdW ferroelectric HHs for future photovoltaic and optoelectronic devices.