Experiments
- AG - astrophysics and geophysics
- BK - biophysics and complex systems
- FM - solid state physics and physics of materials
- KT - nuclear physics and particle physics
FM - solid state physics and physics of materials
- FM.ATE - Analytical Transmission Electron Microscopy of Self-organizing Nanocomposites
- FM.DIF - Diffusion in the solid
- FM.ERH - Recovery and Recrystallization of Aluminum
- FM.FMR - Ferromagnetic Resonance
- FM.HEU - High-harmonic Generation with an Ultrashort-Pulse Laser
- FM.LEE - Low-energy Electron Diffraction (LEED)
- FM.MBE - Molecular Beam Epitaxy and Growth Control by Electron Diffraction (RHEED)
- FM.MEC - Mechanical Behavior of Nanostructured Metals
- FM.MKS - Magnetic Coupling in thin films and magneto-optical Kerr effect
- FM.ORG - Organic Electronics: Charge transport in organic semiconductors
- FM.PHA - Phase Transitions of Iron-Carbon-Alloys
- FM.PLD - Pulsed Laser Deposition and Thin Film Characterization by Spectroscopic Ellipsometry
- FM.QHE - Quantum Hall Effect
- FM.SOL - Solar Cell
- FM.TES - Tunnel Effect in Superconductors
- FM.ULP - Spatial and Temporal Distortion of Ultrashort Light Pulses
- KT.MOE - Mössbauer Spectroscopy
- KT.PIR - Elemental analysis by proton induced X-ray emission (PIXE)
- KT.POV - Positron Annihilation: Coincidence Spectroscopy
FM.QHE - Quantum Hall Effect
Carrier concentration and mobility are essential parameters in the electrical characterisation of semiconductor materials. They can be determined by Hall-Effect and resistivity measurements. Moreover, the temperature dependence of these quantities can be used to extract further information about the material, such as activation energy or relevant scattering mechanisms. For example, two-dimensional electron gases (2DEGs) exhibit a fundamentally different temperature dependence of the mobility as compared to bulk material, due to the absence of scattering from ionised impurities in the 2DEG channel.
Two-dimensional electron gases with high mobility develop plateaus in the Hall resistance at high magnetic fields (Quantum-Hall-Effect,QHE).
In this lab, classical Hall-Effect measurements will be performed on various semiconductor heterostructures. In this way, basic techniques of electrical characterization and low-temperature physics are demonstrated. The results will be analysed in detail, together with the data set of a QHE measurement obtained for the same sample.