Electric field analysis for the design of LT-GaAs photoconductive terahertz antennas

To design photoconductive terahertz antennas with better performance, we have studied the electric field characteristics between the electrodes of the antennas by testing the terahertz radiation pulses emitted from five biased low-temperature-grown GaAs (LT-GaAs) antennas with different gap sizes and electrode shapes. The experimental results indicate that the electric field is mainly distributed near the two electrodes, especially near the anode. Two main reasons of this phenomenon are the different mobilities of the electrons and holes and the Schottky contact between the metal electrode and the substrate.