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HL: Halbleiterphysik

HL 4: Ultrakurzzeitph
änomene

HL 4.10: Vortrag

Montag, 8. März 2004, 12:30–12:45, H13

THz photomixer based on quasi-ballistic transport in AlGaAs nipnip-superlattices — •Frank H. Renner1, O. Klar1, S. Malzer1, M. Eckardt1, A. Schwanhäußer1, G. Loata2, T. Löffler2, H. Roskos2, D. Driscoll3, M. Hanson3, A.C. Gossard3, and G.H. Döhler11Insitut für Technische Physik I, Universität Erlangen-Nürnberg , Germany — 2Lehrstuhl für Ultrakurzzeitphysik, Universität Frankfurt a.M., Germany — 3Materials Departement, UC Santa Barbara, U.S.A.

Conventional THz-photomixers are antenna-structures on a LT-GaAs-layer and are based on the photoconductivity of LT-GaAs, characterized by an extremely short carrier-lifetime . We have developed a novel concept for photomixing based on the quasi-ballisitic transport of electrons in AlGaAs-i-layers. In this concept, the emitter is not limited by the lifetime of the photogenerated carriers and its efficiency proves to be higher than in conventional LT-photomixers.

The emitter consists of a stack of nano-pin-diodes. The lengths and Al-contents of the i-layers in this nipnip-superlattice are optimized for the transport of the carriers. Recombination of the photogenerated carriers takes place inside the recombination-enhanced np-diodes between the nano-pin-diodes. The THz-modulated current is fed into an attached planar antenna, which is either a resonant dipole-antenna or a non-resonant spiral- or log. periodic-antenna.

In this contribution we present the concept of the nipnip-emitter and its realization in the AlGaAs material system, including experimental results on the THz-output and frequency response of the emitter.

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DPG-Physik > DPG-Verhandlungen > 2004 > Regensburg