Optimised THz photoconductive devices based on low-temperature grown III-V compound semiconductors incorporating distributed Bragg reflectors

This study reports work on optimised THz photoconductive antenna switches based on low-temperature grown materials incorporating distributed Bragg reflectors (DBRs). These materials were characterised electrically using Hall effect, mid-infrared reflectivity measurements and fabricated antennas tested under pulsed excitation in a time-domain spectroscopy system. It is shown that the inclusion of DBR results in enhanced THz peak signals by more than twice across the entire operating frequency range. In addition, the devices exhibit significant improvements in the relative THz power, responsivity and optical to electrical efficiency compared with the reference ones.