THz generation and detection using ultrafast, high resistivity III–V semiconductor photoconductors at 1.55 Km pulse excitation

摘要

THz devices have been fabricated and evaluated as emitters and detectors in a time-domain spectroscopy (TDS) system. The devices employed planar aperture and dipole antenna geometries, which were made on the surface of novel Be doped lattice matched InGaAs-InAlAs multiple quantum well (MQW) structures grown at low temperature (LT) using Molecular Beam Epitaxy (MBE. Such structures exhibited high dark resistivity (> 105 Ω/sq), very short carrier lifetimes (< 200 fs) and relatively high mobility (400 – 1800 cm2/Vs). These properties resulted in system responses with THz pulses having spectral range up to 3 THz and power to noise ratio of 60 dB, which are among the highest ever reported for this material system.