Ultrathin Silicon Nanomembrane in a Tubular Geometry for Enhanced Photodetection

Advanced 3D mesostructures have prominent applications in flexible electronics, photonics, mechanics, and biomedicine. Here, 3D tubular silicon photodetectors are demonstrated by self-rolling ultrathin silicon nanomembranes with enhanced broadband photodetection and responsivity. Strain distributions within the unique circular structures are investigated with micro-Raman spectroscopy, while the tensile strain of the rolled-up microtubes can be controlled with the tube diameter by modifying the membrane thickness and etching parameters during the rolled-up process. The tubular photodetector exhibits increased photocurrent and suppressed dark current compared with planar devices over a wide incident angle. This study provides a novel approach to construct high-performance omnidirectional Si-based photodetectors and offers promising prospects for design and manufacture of complex 3D optoelectronic devices.