Conductivity-Improved One-Dimensional ZnO:Ga/ZnMgO Core–Shell Nanoarray for Fast-Responsed Ultraviolet Photodetector

One-dimensional (1D) nanomaterials have been demonstrated excellent optoelectronic properties and rich physical implications, particularly inherent advantages and potential for three-dimensional multifunctional optoelectronic integration. However, the general long distance between the top-bottom planar electrodes causes a long charge transport channel, further leads a weak effective electric field and serious charge transport loss along the axial direction of the 1D nanoarray, ultimately limits the device performance. Herein, Ga-doped ZnO nanorods were designed and fabricated as the 1D conductive core electrode array via a simple hydrothermal method, followed by sputtering a ZnMgO shell to construct 1D photodetectors. Systematic characterizations about morphology, crystallization, optical, and electrical properties reveal the optimized doping concentration of 1 mol %, yielding a conductivity enhancement of approximately 5 orders of magnitude compared to undoped ZnO. With reduced axial transport resistance, the ZnO:Ga/ZnMgO core–shell device exhibits a response time of ∼80 ms, compared to ∼3 s for the undoped counterpart under identical conditions. These results demonstrate conductivity engineering of 1D nanoarrays as an effective strategy for suppressing carrier transport loss and enabling fast-speed integrated optoelectronic devices.