Contact

Prof. (apl.) Dr. Jürgen Weis
Head of the Nanostructuring Lab
Phone:+49 711 689-1329Fax:+49 711 689-1572

Max Planck Institute for Solid State Research

Heisenbergstraße 1, 70569 Stuttgart

Publications

Quantum dots, also denoted as artifical atoms or zero-dimensional electron systems, are objects where few to many electrons are confined in a small spatial enclosure of mesoscopic size (few tens to few hundreds of nanometers), allowing  a single electron only certain eigenvalues for its energy (‘quantum mechanical particle in a box’).

Electrical Properties of Quantum Dot Systems

Quantum dots, also denoted as artifical atoms or zero-dimensional electron systems, are objects where few to many electrons are confined in a small spatial enclosure of mesoscopic size (few tens to few hundreds of nanometers), allowing  a single electron only certain eigenvalues for its energy (‘quantum mechanical particle in a box’). [more]
Measuring the Hall resistance on a two-dimensional charge carrier system at low magnetic fields allows determining the charge carrier concentration and the type of charge carrier (electron or hole). However at high magnetic field values (and low temperature), magnetic field intervals appear where the measured value is constant and well described by |RH|= h/ie2.

Locally Probing Quantum Hall Samples

Measuring the Hall resistance on a two-dimensional charge carrier system at low magnetic fields allows determining the charge carrier concentration and the type of charge carrier (electron or hole). However at high magnetic field values (and low temperature), magnetic field intervals appear where the measured value is constant and well described by |RH|= h/ie2. [more]
Scanning probe microscopy investigating quantum Hall samples has been performed in our group for many years and has led to a microscopic picture for the current distribution in quantum Hall samples which contradicts the current-carrying edge-state model.

Microscopic Picture of the Quantum Hall Effect

Scanning probe microscopy investigating quantum Hall samples has been performed in our group for many years and has led to a microscopic picture for the current distribution in quantum Hall samples which contradicts the current-carrying edge-state model. [more]
Two-paths quantum Hall devices have been discussed in literature in terms of the edge-state picture as electronic interferometers. Our recent experimental investigations on a versatile mesoscopic quantum Hall device with in-situ tunable different combinations of parallel current paths shows in all combinations periodic conductance modulations in the applied magnetic flux.

Two-Paths Quantum Hall Devices

Two-paths quantum Hall devices have been discussed in literature in terms of the edge-state picture as electronic interferometers. Our recent experimental investigations on a versatile mesoscopic quantum Hall device with in-situ tunable different combinations of parallel current paths shows in all combinations periodic conductance modulations in the applied magnetic flux. [more]
The transmission time tHa of an incident Gaussian wave packet through a barrier is usually taken as the difference between the time at which the peak of the transmitted packet leaves the barrier of thickness ℓ and the time at which the peak of the incident Gaussian wave packet arrives at the barrier. This yields a corresponding transmission velocity cHa = ℓ/tHa which appears under certain conditions as a supervelocity.

Supervelocities in Tunneling?

The transmission time tHa of an incident Gaussian wave packet through a barrier is usually taken as the difference between the time at which the peak of the transmitted packet leaves the barrier of thickness and the time at which the peak of the incident Gaussian wave packet arrives at the barrier. This yields a corresponding transmission velocity cHa = ℓ/tHa which appears under certain conditions as a supervelocity. [more]
The physics of organic solar cells und organic light emitting diodes has been explored in a common work with the company BASF SE in Ludwigshafen, Germany.

Organic Electronics

The physics of organic solar cells und organic light emitting diodes has been explored in a common work with the company BASF SE in Ludwigshafen, Germany. [more]
Within the Nanostructuring Lab, various substrates – conventional and unconventional – have to be structured by high resolution electron-beam lithography. The density and area size of the written pattern varies from application to application. Diverse resists have to be used, acting either as etching or lift-off mask. Facing a large variety of combinations, we have to challenge electron beam lithography.

Electron Beam Lithography

Within the Nanostructuring Lab, various substrates – conventional and unconventional – have to be structured by high resolution electron-beam lithography. The density and area size of the written pattern varies from application to application. Diverse resists have to be used, acting either as etching or lift-off mask. Facing a large variety of combinations, we have to challenge electron beam lithography. [more]
With January 1st 2011, the cleanroom facility (previously a facility of the von Klitzing department) became part of the newly established Scientific Facility Nanostructuring Lab. Under class-10 cleanroom conditions with stable room humidity and temperature, samples can be processed by students of the Institute or in service by the cleanroom staff using photolithography, dry and wet etching, and material deposition under vacuum.

Nanostructuring Lab

With January 1st 2011, the cleanroom facility (previously a facility of the von Klitzing department) became part of the newly established Scientific Facility Nanostructuring Lab. Under class-10 cleanroom conditions with stable room humidity and temperature, samples can be processed by students of the Institute or in service by the cleanroom staff using photolithography, dry and wet etching, and material deposition under vacuum. [more]
 
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