Excitation and bias voltage-dependence of the terahertz emission from low-temperature-grown photoconductive antenna devices at different temperatures

Abstract

We investigated the temperature dependence of the terahertz (THz) emission in a low-temperature grown gallium arsenide (LT-GaAs) photoconductive antenna (PCA) via an equivalent circuit model (ECM) that accounts for the PCA carrier dynamics. A parametric analysis was done by varying either the laser power or the voltage bias whilst taking all the other parameters constant. Results show that increasing the operating temperature decreases the THz emission intensity, and bandwidth. The THz peak amplitude exhibit a linear trend at low power and voltage values. When the material's voltage breakdown is not considered, at low temperatures a higher bias could be applied to the PCA before voltage screening and carrier velocity saturation occur. Insights from this work contribute to the design optimization of PCA systems to increase overall efficiency.