Dresden 2003 – scientific programme
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HL: Halbleiterphysik
HL 42: Bauelemente I
HL 42.6: Talk
Thursday, March 27, 2003, 13:00–13:15, BEY/118
Highly doped LT-GaAs and ErAs layers as recombination centers for nipnip-THz-photomixers — •Frank Renner1, M. Eckardt1, A. Schwanhäuser1, A. Friedrich1, P. Pohl1, Ö. Yüksekdag1, O. Schmidt1, S. Malzer1, P. Kiesel2, D. Driscoll3, M. Hanson3, A. Gossard3, and G.H. Döhler1 — 1Institute of Technical Physics 1, Erlangen, University Erlangen-Nuremberg — 2Palo Alto Research Center Inc., Palo Alto, USA — 3Materials Department, University of California, Santa Barbara
We have recently developed a new concept for THz generation by photomixing in nipnip-superlattices using the ballistic flight of the photogenerated carriers. The realization of the emitter critically depends on the recombination currents in the pn-diodes. These currents have to exceed those observed under forward bias in standard pn-diodes by many orders of magnitude. In this talk, we report on two main approaches for the realization of such diodes: GaAs pn-diodes with a highly doped n-LT-GaAs-layer grown at different temperatures and GaAs diodes with ErAs recombination layers between the junction.
Current densities of 1 kA/cm2 at 1V in the case of the LT-samples and more than 7 kA/cm2 for "ErAs-diodes" can be achieved at room temperature. In addition, we present temperature-dependent IV-curves, which show significant differences in the forward bias characteristics. This is caused by the different nature of the recombination layers which is proven by simple models. They indicate that ErAs is acting as a metallic layer inside the pn-junction.