Ultra-fast and high-responsivity self-powered vis−NIR photodetector via surface charge transfer doping in MoTe 2 /ReS 2 heterostructures

Abstract The development of optoelectronic technologies demands photodetectors with miniaturization, broadband operation, high sensitivity, and low power consumption. Although 2D van der Waals (vdW) heterostructures are promising candidates due to their built-in electric fields, ultrafast photocarrier separation, and tunable bandgaps, defect states limit their performance. Therefore, the modulation of the optoelectronic properties in such heterostructures is imperative. Surface charge transfer doping (SCTD) has emerged as a promising strategy for non-destructive modulation of electronic and optoelectronic characteristics in two-dimensional materials. In this work, we demonstrate the construction of high-performance p−i−n vertical heterojunction photodetectors through SCTD of MoTe 2 /ReS 2 heterostructure using p-type F 4 -TCNQ. Systematic characterization reveals that the interfacial doping process effectively amplifies the built-in electric field, enhancing photogenerated carrier separation efficiency. Compared to the pristine heterojunction device, the doped photodetector exhibits remarkable visible to near-infrared (635−1064 nm) performance. Particularly under 1064 nm illumination at zero bias, the device achieves a responsivity of 2.86 A/W and specific detectivity of 1.41 × 10 12 Jones. Notably, the external quantum efficiency reaches an exceptional value of 334% compared to the initial 11.5%, while maintaining ultrafast response characteristics with rise/fall times of 11.6/15.6 μ s. This work provides new insights into interface engineering through molecular doping for developing high-performance vdW optoelectronic devices.