Demonstration of a 3D-Assembled Dual-Mode Photodetector Based on Tubular Graphene/III–V Semiconductors Heterostructure and Coplanar Three Electrodes

3D assembly technology is a cutting-edge methodology for constructing high-performance and multifunctional photodetectors since some attractive photodetection features such as light trapping effect, omnidirectional ability, and high spatial resolution can be introduced. However, there has not been any report of 3D-assembled multimode photodetectors owing to the lack of design and fabrication guideline of electrodes serving for 3D heterostructures. In this study, a 3D-assembled dual-mode photodetector (3DdmPD) was realized successfully via the clever electrical contact between the rolled-up tubular graphene/GaAs/InGaAs heterostructure and planar metal electrode. Arbitrary switching of three coplanar electrodes makes the as-fabricated tubular 3D photodetector work at the unbiased photodiode mode, which is suitable for energy conservation high-speed photodetection, or the biased photoconductive mode, which favors extremely weak light photodetection, fully showing the advantages of multifunctional detection. In more detail, the