Magnetotransport and THz-Optical Investigations at Devices with HgTe Quantum Wells
| Autor: | J. Könemann, M. Bugár, G. Nachtwei, F. Gouider, Yu. B. Vasilyev, C. Brüne, H. Buhmann |
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| Rok vydání: | 2010 |
| Předmět: |
Physics
Condensed matter physics business.industry Terahertz radiation Photoconductivity Physics::Optics Landau quantization Quantum Hall effect Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Condensed Matter Physics Laser Atomic and Molecular Physics and Optics law.invention Effective mass (solid-state physics) law Optoelectronics General Materials Science Charge carrier business Quantum well |
| Zdroj: | Journal of Low Temperature Physics. 159:184-188 |
| ISSN: | 1573-7357 0022-2291 |
| DOI: | 10.1007/s10909-009-0115-5 |
| Popis: | We investigated the magnetoconductivity and the Terahertz (THz) photo-conductivity of devices with HgTe quantum wells embedded in barrier layers of HgCdTe. For the photoconductivity measurements, a THz laser system (p-Ge-Laser) is applied. This laser uses transitions between Landau levels of light holes in Ge and emits laser pulses in the wavelength range 120 μm < λ < 180 μm. The THz laser radiation is used in order to excite charge carriers over the Landau-gap. The response of the sample to the laser impulses is in 2D-samples in the quantum Hall (QH) regime measured in order to receive data of the relaxation of the charge carriers. In this presentation we present photoconduction measurements of the HgTe-quantum well in Hall bar, Corbino as well as combined Corbino-Hall bar geometry in the QH-regime. The material system HgTe/HgCdTe is characterized by a small effective mass (compared to GaAs, in our case 0.023 m0) and accordingly smaller magnetic fields for the appropriate cyclotron energy. Thus, this material combination provides the opportunity to make THz detectors using magnetic fields below 2 T for operation. |
| Databáze: | OpenAIRE |
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