Plasmon-Induced Enhancement of Infrared Detection Using a Carbon Nanotube Diode

It is demonstrated that a plasmonic contact electrode can significantly enhance the performance of carbon nanotube (CNT) infrared (IR) detectors based on a barrier-free bipolar diode. The use of an axe-like plasmonic electrode suggests a considerably stronger field near the electrode with efficient collection of carriers, simultaneously enabling an enhancement from 1400 to 2100 nm. Particularly, it shows an explicit photocurrent enhancement where the polarization of incident light is perpendicular to a CNT. The best photocurrent enhancement of a plasmonic detector can be nearly 200 times larger than that without a plasmonic structure. Further investigation demonstrates that the enhancement is due to an enhancement effect caused by the manipulation of the electric field distribution near the axe-like contact electrode and the contribution of the plasmonic concentration. The enhancement shows a typical dependence on the position of CNTs corresponding to the axe-like structure, and an enhancement larger than 600 times can be achieved by further tuning the gate voltage. Using the plasmonic contact electrode, the disadvantage of a weak CNT response to perpendicular polarized illumination can be overcome. Meanwhile, the plasmonic electrode significantly improves the utilization of incident light in the IR detection application.National Key Research & Development Program [2016YFA0201902]; National Science Foundation of China [61370009, 61321001]SCI(E)ARTICLE6