Surface modulation of two-dimensional perovskite for spatially selective p-type doping in van der Waals stacked MoS2 toward high-performance homojunction photodetector

Homogeneous p–n junctions in two-dimensional transition metal dichalcogenides (e.g., MoS2) demonstrate significant potential in high-performance optoelectronic devices. However, achieving stable and controllable p-type doping in MoS2 remains challenging, hindering the construction of high-quality p–n homojunctions. Traditional doping methods such as chemical adsorption or gate voltage modulation often suffer from issues like poor stability or complex fabrication processes. This study revealed that oxygen plasma treatment effectively modulated the surface morphology and potential of two-dimensional perovskite (2DPVK) nanosheets grown by a floating solution growth method. Furthermore, by establishing a van der Waals interface between processed 2DPVK and MoS2, successful reconfiguration of carrier polarity in MoS2 was achieved. This enabled the fabrication of lateral MoS2 homogeneous p–n junctions by spatially selective treatment of 2DPVK. The homojunction device exhibited pronounced rectification characteristics and maintained a low dark current. Under laser illumination, the photocurrent increased by four orders of magnitude relative to the dark current, and the open-circuit voltage reached 0.6 V. Photocurrent mapping further revealed the dominant role of the built-in electric field in carrier separation. In the self-driven (zero bias) mode, the device demonstrates a high responsivity of 0.33 A W−1. This study successfully achieved selective p-type doping of MoS2 through interface-engineered van der Waals stacking, which provides innovative insights for controllable design in high-efficiency optoelectronic devices based on two-dimensional materials.