Novel p-p Heterojunctions Self-Powered Broadband Photodetectors with Ultrafast Speed and High Responsivity

Novel inorganic/organic self-powered UV-vis photodetectors based on single Se microtube and conducting polymers-polyaniline (PANI), polypyrrole (PPy), and poly(3,4-ethylenedioxythiophene) (PEDOT)-are fabricated. The conducting polymers are directly coated on the surface of a single Se microtube via a facile and low-cost in situ polymerization method. The integrated Se/PANI photodetector with 45-nm-thick PANI layer shows excellent self-powered behavior under UV-vis light illumination. In particular, it exhibits high on/off ratio of 1.1 x 10(3), responsivity (120 mA W-1), large detectivity (3.78 x 10(11) Jones), and ultrafast response speed (rise time of 4.5 mu s and fall time of 2.84 ms) at zero bias at 610 nm (0.434 mW cm(-2))-light illumination. Moreover, the individual Se/PPy and Se/PEDOT self-powered photo-detectors also exhibit fast and stable responses, including responsivity of 70 and 5.5 mA W-1, rise time of 0.35 and 1.00 ms, fall time of 16.97 and 9.78 ms, respectively. Given the simple device architecture and low cost fabrication process, this work provides a promising way to fabricate inorganic/organic, high-performance, self-powered photodetectors.