20 research outputs found
Influence of etching processes on electronic transport in mesoscopic InAs/GaSb quantum well devices
We report the electronic characterization of mesoscopic Hall bar devices
fabricated from coupled InAs/GaSb quantum wells sandwiched between AlSb
barriers, an emerging candidate for two-dimensional topological insulators. The
electronic width of the etched structures was determined from the low field
magneto-resistance peak, a characteristic signature of partially diffusive
boundary scattering in the ballistic limit. In case of dry-etching the
electronic width was found to decrease with electron density. In contrast, for
wet etched devices it stayed constant with density. Moreover, the boundary
scattering was found to be more specular for wet-etched devices, which may be
relevant for studying topological edge states.Comment: 5 pages, 2 figure
Mapping an electron wave function by a local electron scattering probe
A technique is developed which allows for the detailed mapping of the electronic wave function in
two-dimensional electron gases with low-temperature mobilities up to 15 10 cm V s ´ 6 2 11 - - . Thin
(‘delta’) layers of aluminium are placed into the regions where the electrons reside. This causes
electron scattering which depends very locally on the amplitude of the electron wave function at the
position of the Al δ-layer. By changing the distance of this layer from the interface we map the shape of
the wave function perpendicular to the interface. Despite having a profound effect on the electron
mobiliy, the δ-layers do not cause a widening of the quantum Hall plateaus.peerReviewe