Dynamical Conductivity of Lateral Superlattices


Keywords: quantum devices, superlattices, heteroepitaxy, infrared detectors

Start Date: 1 January 93 / Status: finished / Duration: 36 months

[ participants / contact]

Objectivies and Approach

The objective of this project is to study the properties of lateral superlattices defined on state-of-the-art semiconductor material. The reduced dimensionality is expected to lead to a number of new physical effects, some of which could be crucial to a new generation of quantum devices. The project uses GaAs-based material but it includes a study of properties of a new material system InAs/AlSb which is very promising for lateral pattering. Also, more conventional superlattices are investigated as they have many parallels to lateral superlattices but with a carefully controlled potential.

European links: ESPRIT BRA working group QUANTECS (6312) and network PHANTOMS (7360).

Progress and Results

As/AlSb: A series of experiments has shown how the inter-subband resonance linewidth is reduced well beyond the single particle homogeneous broadening. The first photoconductivity experiments have been carried out.

Parabolic wells: Superlattices with confinement in one direction but with free motion in the other two directions are studied by embedding a superlattice potential in a parabolic quantum well.

Self-assembled quantum dots: By terminating the growth of InAs on GaAs after just a few monolayers, it is possible to generate very small (20 nm) and remarkably homogeneous dots of InAs that can be loaded electron by electron. Studies of the properties of these dots are underway.

Information Dissemination Activities and/or Exploitation

The results of the project have been published in some forty papers in the past three years and presented at a large number of international conferences, with seven invited talks in the last year of the project alone.

The work within DCLS constitutes fundamental research for future devices, for instance tunable infra-red detectors based on InAs as well as single-electron and optical devices based on the self-assembled quantum dots.


Sektion Physik der Universität München
Geschwister-Scholl-Platz, 1
D - 80539 München, D

EU Partners

Universität München, D
Thomson-CSF/LCR, F
Delft University of Technology, NL
University of Glasgow, UK
University of Nottingham, UK

Non-EU Partners

University of California at Santa Barbara, USA


Prof. Jorg P. Kotthaus
Phone: +49 89 2180 3737
Fax: +49 89 2180 3182
E-mail: jorg.kotthaus@physik.uni.muenchen.de

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DCLS - EC-US015, May 1997

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html version of synopsis by Nick Cook