Influence and adjustment of carrier lifetimes in InGaAs/InAlAs photoconductive pulsed terahertz detectors: 6 THz bandwidth and 90dB dynamic range.

We investigate the influence of Beryllium (Be) doping on the performance of photoconductive THz detectors based on molecular beam epitaxy (MBE) of low temperature (LT) grown In(0.53)Ga(0.47)As/In(0.52)Al(0.48)As multilayer heterostructures (MLHS). We show how the optical excitation power affects carrier lifetime, detector signal, dynamic range and bandwidth in THz time domain spectroscopy (TDS) in dependence on Be-doping concentration. For optimal doping we measured a THz bandwidth in excess of 6 THz and a dynamic range of up to 90 dB.