Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

We present studies on nonresonant photoconductive THz detectors and emitters. Our system consists of a large-area terahertz detector based on an interdigitated electrode structure and an emitter with similar electrode geometry [1]. Emitters based on this concept stand out due to their high efficiency for conversion of near-infrared radiation into far-infrared radiation. The main advantage of the scalable antennas as compared to conventional photoconductive antennas is that they do not require tight focusing of the THz and gating beams. While the emitter is fabricated on semi-insulating GaAs, we compare different detection antennas based on ion-implanted and low temperature grown (LT) GaAs, respectively. We discuss which material properties affect the performance and noise level of our system and discuss the role of the carrier lifetime upon the measured THz signal. The best signal-tonoise ratios are found for N+ dual energy implantations (0.4 MeV and 0.9 MeV) with doses in the 1013 cm−2 range and for (LT) GaAs.
[1] F.Peter, S.Winnerl, S. Nitsche, A. Dreyhaupt, H. Schneider, M.Helm, Appl. Phys. Lett. 91, 081109 (2007)