Improvement of terahertz emission in gallium arsenide photoconductive antennas coated with silicon nanowires via dropcasting
We report on the enhancement in the terahertz (THz) emission of a gallium arsenide (GaAs) photoconductive antenna (PCAs) coated with silicon nanowires (SiNWs). The SiNWs were synthesized using metal-assisted chemical etching, and applied onto the PCAs by dropcasting. The THz emission from the SiNW-coated PCA was observed to have up to three times peak-to-peak THz-TDS waveform enhancement over its uncoated counterpart. A possible origin for the enhancement is the improved light-trapping and photoabsorption in the SiNW-coated sample, but is currently unable to completely account for it.