Thin film tandem nanoplasmonic photoconductive antenna for high performance terahertz detection

Photoconductive antennas (PCA) have attracted lots of attention for terahertz application, due to their room temperature operation and compact design. On the other hand, their main problem is acquiring low output power. Lately, plasmonic structures of different geometries have been proposed to overcome the mentioned issue. Here, we have proposed and simulated a PCA on a silicon-on-sapphire substrate and a layout of a plasmonic nanostructure in which the effect of geometrical parameters of the nanostructure on PCA's output was investigated and optimized. According to the results for one layer plasmonic nanostructure, two different geometries showed more than 700% improvement in the device photocurrent which are related to different types of surface plasmons. By combining these layouts and benefiting from both simultaneously, a final proposed nanostructure was constructed. After optimizing the new structure's parameters, a significant increase of 15400% in photocurrent enhancement was achieved by comparing to the conventional THz PCAs on similar substrate.