Terahertz Emission Enhancement of Gallium-Arsenide-Based Photoconductive Antennas by Silicon Nanowire Coating

In this article, we report on the enhancement of the terahertz (THz) emission characteristics of gallium arsenide-based photoconductive antennas (PCAs) upon coating with silicon nanowires (SiNWs). The SiNWs were fabricated using metal-assisted chemical etching and were dropcasted onto PCAs with dipole antenna patterns. The THz emission of the SiNW-coated PCA was observed to increase up to three times with respect to the uncoated sample. Possible mechanisms leading to the emission enhancement are proposed in the context of increased photoabsorption and capacitance induced by the SiNWs. The results demonstrate the proof of a low-cost method of enhancing the PCA performance by utilizing nanostructures.