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

Abstract

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.

Terahertz Pulse Detection Techniques and Imaging Applications

“…Photoconductive and EO methods are able to provide large detection bandwidth for THz pulses, which is useful for spectroscopy. As for photoconductive sampling, there are many studies and promising results [25][26][27][28][29][30][31][32]. (i) The sensitivity, THz bandwidth and dynamic range of THz pulse detection are improved by fabricating photoconductive antennas on InGaAs/InAlAs multilayer heterostructures [25,26].…”

Towards Quality Control in Pharmaceutical Packaging: Screening Folded Boxes for Package Inserts

“…The laser includes a dispersioncompensating fiber, followed by a standard polarization-maintaining fiber, which guides the pulses to the terahertz emitter. The emitter (Fraunhofer Heinrich Hertz Institute, model THz-PTx) consists of an InGaAs/InAlAs photoconductive switch with a strip-line antenna [17]. With an optical power of 20 mW and a DC bias of 120 V applied, the emitter generates an average terahertz power of approx.…”

Terahertz detectors from Be-doped low-temperature grown InGaAs/InAlAs: Interplay of annealing and terahertz performance

“…[42][43][44] Recently, the influence of Be doping of LTG-InGaAs/InAlAs heterostructures on the performance as THz photoconductive detectors was described. 6 It was shown, that the spectral roll-off, the amplitude of the detected THz pulse and the noise-level were strongly influenced by this parameter. In this publication we studied samples with carrier lifetimes below 300 fs but significantly different electrical properties as THz photoconductive detectors.…”

“…3,4 LTG-InGaAs based photoconductors are the state-of-the art detector antennas in commercially available THz time-domain spectroscopy (THz-TDS) systems. 5,6 However, the improvement of devices fabricated from LTG-InGaAs based materials demands a fundamental understanding of the properties of the material itself.…”