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HL: Halbleiterphysik

HL 9: Poster I

HL 9.101: Poster

Montag, 27. März 2006, 15:15–17:45, P3

Photoconductivity measurements on Terahertz-HgTe/HgCdTe-Quantum-Hall-detectors — •R. Bonk¹, C. Stellmach¹, C. Becker², V. Hock², G. Hein³, and G. Nachtwei¹ — ¹Institut für Angewandte Physik, TU-Braunschweig, Mendelssohnstr.2, D-38106 Braunschweig — ²Fakultät für Physik und Astronomie, Julius-Maximilians-Universität Würzburg, Am Hubland, D-97074 Würzburg — ³Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig

Many Terahertz-(THz) applications from material research to biological systems have stimulated an intense research in the field of THz wave detection. Two- dimensional electron systems under quantum hall-(QH) conditions develop energy gaps of the order of 10 meV between the Landau levels. Therefore, these systems can interact effectively with far-infrared radiation with wavelengths of the order of 100 µm. Hence, it was found that QH-systems can be used for fast THz detectors with spectral selectivity. In this work we present THz- photoconductivity-(PR) measurements on MCT-(HgCdTe/HgTe)-quantum wells. A pulsed p-Ge laser (120-180 µm) and a glow bar were used as THz sources. With the pulsed monochromatic laser radiation quasi-time resolved PR is measured. The results are relaxation times-(RT) (dissipative to QH state) limited by the experimental setup in the µm range. Additionally, we are interested in the spectral resolution and in the sensitivity of THz-QH-detectors. MCT samples show a sensitivity of the irradiated FIR power, but no visible reaction in the strong bolometric signal to different laser energies.