Plasmonic Tunnel Diode and Photodetector based on Layer‐Stacked AuNP‐Nanomembrane/p‐Si Heterojunction

Abstract

AbstractElectronic devices with rectifying effect are typical building blocks for integrated circuits and useful for photodetectors. Herein, a new type of diode based on plasmonic tunnel hetero‐nanostructure is reported. By constructing a planar plasmoelectric junction between p‐Si and Au pad electrode with a few‐layer‐stacked 2D plasmonic AuNP‐nanomembrane as a medium layer, rectifying behavior of the device is achieved, though the direct contact between bulk Au and semiconductor usually tends to form ohmic contact. The electrically driven plasmons enable the 2D AuNP‐nanomembrane to be electron‐rich, while the asymmetric band alignment which causes bidirectionally different barrier at the (buried) interface results in the unidirectional rectifying behavior of the constructed plasmonic diode (p‐diode). The planar junction made of shell‐isolated Au@SiO2 NP‐nanomembrane (instead of AuNP‐nanomembrane) shows still rectifying behaviors but better photoresponse, due to structurally well‐defined/ordered nanostructures and intensified plasmonic tunneling effect of the nanomembrane. The as‐constructed p‐diode‐based photodetector with Au@SiO2 NP‐nanomembrane shows impressive photoresponse with a high photoresponsivity value of 6.496 A W‐1 and a detectivity value of 1.9859 × 1011 Jones under the 268 µW cm‐2 650 nm laser irradiance, comparable to the reported values of similar devices prepared from other 2D materials.