Effect of Doped Buffer in Low-Temperature-Grown GaAs Terahertz Photoconductive Antenna Emitters and Detectors

Terahertz (THz) photoconductive antenna (PCA) fabricated on low-temperature-grown GaAs (LT-GaAs) with layer structure consisting of a doped buffer exhibited enhanced THz emission for LT-GaAs grown at lower temperature. As THz emitter, the LT-GaAs grown at 270°C with doped buffer generated THz radiation with amplitude twice as that of its undoped counterpart. Similar effect is not observed when the LT-GaAs is grown at 320°C with doped buffer, which is expected to have higher THz emission. As THz detector, both LT-GaAs with doped buffer exhibited identical and improved detection sensitivity regardless of the LT-GaAs growth temperature.