Observation of polarity-switchable photoconductivity in lInitride/MoS_(x)core-shell nanowires

Ⅱ-Ⅴsemiconductor nanowires are indispensable building blocks for nanoscale electronic and optoelectronic devices.However,solely relying on their intrinsic physical and material properties sometimes limits device functionalities to meet the increasing demands in versatile and complex electronic world.By leveraging the distinctive nature of the one-dimensional geometry and large surface-to-volume ratio of the nanowires,new properties can be attained through monolithic integration of conventional nanowires with other easy-synthesized functional materials.Herein,we combine high-crystal-quality lInitridle nanowires with amorphous molybdenum sulfides(a-MoS)to construct II.nitride/a-MoS_(x) core-shell nanostructures.Upon light ilumination,such nanostructures exhibit striking spectrally distinctive photodetection characteristic in photoelectrochemical environment,demonstrating a negative photoresponsivity of-100.42 mA W^(-1)under 254 nm ilumination,and a positive photoresponsivity of 29.5 mA W^(-1)under 365 nm ilumination.Density functional theory calculations reveal that the successful surface modifcation of the nanowires via a-MoS_(x)decoration accelerates the reaction process at the electrolyte/nanowire interface,leading to the generation of opposite photocurrent signals under different photon ilumination.Most importantly,such polarity-switchable photoconductivity can be further tuned for multiple wavelength bands photodetection by simply adjusting the surrounding environment and/or tailoring the nanowire composition,showing great promise to build light-wavelength controllable sensing devices in the future.