Epitaxial growth of 2DEGs: III-V heterostructures

Contacts: Ulf GENNSER and Bernard ETIENNE  

This research activity is centred around the epitaxial growth of GaAs-based two-dimensional electron gases (2DEGs) for the study of electronic transport properties. In these 2DEGs the electron mean free path at low temperatures can be several tenths of micrometers, and the quantum phase can be preserved for up to a quarter of a mm. They are therefore the supreme ‘work horse’ for mesoscopic physics, where we try to understand the convergence between electronic transport and quantum mechanical properties.

2DEGs in the GaAs/AlGaAs material system, grown using molecular beam epitaxy (MBE), can attain very high mobilities, with electron mean free paths of tens or even hundreds of microns. In this action we use our high-purity III-V MBE system to elaborate high mobility 2 DEGs for studies in a wide variety of fields. GaAs/AlGaAs heterojunctions containing 2 DEGs with specially adjusted carrier densities and / or distance to the surface are developed for:

as well as for a number of external collaborations


We also investigate "non-conventional" 2 DEGs. These can be two-dimensional hole gases or 2 DEGs in AlAs quantum wells, where the band degeneracies, anisotropic masses, and spin-orbit interactions can lead to novel physics. Currently, our main effort here are on 2 DEGs in membrane structures, which can be used in thermodynamic studies and for nano-electro-mechanical devices.




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