High-sensitivity photoconductive detectors with wide dipole electrodes for low frequency THz wave detection

Abstract

Photoconductive detectors (PCDs) with wide dipole electrodes were fabricated on low temperature-grown GaAs for observation of low frequency terahertz electromagnetic waves. The screening effect in PCDs caused by the space charge of photoexcited electron-hole pairs brings poor sensitivity in detection. This can be effectively reduced by widening the dipole electrodes in PCDs. The width dependence of terahertz (THz) wave detection properties of PCDs showed that not only the sensitivity but also the signal-to-noise ratio can be fairly improved by increasing the width, especially at frequencies lower than 1.2 THz.