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A new method of generating and detecting terahertz waves is proposed.Low-temperature-grown gallium arsenide(LT-GaAs) thin films are prepared by etching a sacrificial layer (AlAs) in a four-layer epitaxial structure constituted with LT-GaAs,AlAs,GaAs,and semi-insulating gallium arsenide (SI-GaAs).The thin films are then transferred to clean silicon for fabricating the LT-GaAs thin film antennas.The quality and transmission characteristics of the films are analyzed by an 800-nm asynchronous ultrafast time domain spectroscopy system,and the degree of bonding between the film and silicon wafer is determined.Two LT-GaAs thin film antennas for generating and detecting the terahertz waves are tested with a 1550-nm femtosecond laser.The terahertz signal is successfully detected,proving the feasibility of this home-made LT-GaAs photoconductive antennas.This work lays a foundation for studying the mechanism of terahertz wave generation in GaAs photoconductive antennas below the semiconductor band gap.