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

Abstract

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.