Omnidirectional and Highly Sensitive Microtubular Photodetectors Based on QD/2D Heterojunctions

Roll-up technology provides a feasible approach to transform patterned planar membranes into three-dimensional (3D) tubular microstructures. The tubular geometry enables the confinement of the local electromagnetic field and strengthens the photon-matter interaction inside the structure. By applying the roll-up method, we fabricated 3D tubular photodetectors from graphene/quantum dots (QDs) embedded polymer membranes around an optical fiber. These fabricated tubular photodetectors exhibit 5 times higher photoresponsivity compared to their planar counterparts. The enhanced responsivity is related to the light-trapping effect of the tubular structure as verified by the finite-difference time-domain (FDTD) simulation. 3D tubular photodetectors can detect photons accurately over a wide incidence angle (0-360 degrees) without the responsivity decline. This unprecedented feature suppresses all published reports and lifts the restriction of the limited measured angle in conventional photodetectors. The omnidirectional and highly sensitive tubular QDs/2D-based devices, opening a route toward future optoelectronic devices from imaging to tracking solar cells.