In this letter, we present low-temperature grown GaAs (LTG-GaAs)-based photoconductive antennas for the generation and detection of terahertz (THz) waves. The growth of LTG-GaAs and the annealing temperatures are systematically discussed based on the material characteristics and the properties of THz emission and detection. The optimum annealing temperature depends on the growth temperature, which turns out to be $540^{circ}C$ to $580^{circ}C$ for the initial excess arsenic density of $2{ imes}10^{19}/cm^3$ to $8{ imes}10^{19}/cm^3$.