Photoconductive THz detector based on new functional layers in multi-layer heterostructures

Characteristics of photoconductive antennas (PCAs) based on InGaAs/InAs/InAlAs superlattice heterostructures exhibiting different types of elastic strain in the layers are compared experimentally. THz signals, noise characteristics, and signal-to-noise ratios of the PCA-detectors were compared by means of a laboratory pulsed time-domain THz spectrometer at different levels of average optical-probe power. A larger detection bandwidth in entire range of probe power is demonstrated experimentally for PCA-detectors based on superlattice heterostructures exhibiting both compressive and tensile strain compared to lattice-matched superlattice heterostructures. It can thus be stated that modification of properties of superlattice heterostructures by introducing strain in the crystal lattice represents a universal and relatively efficient method of improving characteristics of PCAs based on such heterostructures, which allows using these PCAs for development of THz spectroscopy and imaging systems.