Gating of InAs/GaSb quantum wells using a silicon monoxide gate insulator

Abstract

We report on a technique we have recently developed to fabricate very high quality gates and gated structures on InAs/AlxGa1−xSb quantum wells. The low thermal budget process leads to highly stable gates with extremely low leakage currents. Both electron and hole concentrations can be changed over a wide range by the application of modest gate voltages. We obtain a dn/dV value of 5×1011 cm2/V for electrons and 1.6×1012 cm2/V for holes at 1.2 K.

Interlayer current near the edge of an InAs/GaSb double quantum well in proximity with a superconductor

“…4. This is obvious for the 60 nm mesa step sample, but it is also the case for the photolithographically fabricated contacts to the 80 nm mesa step sample, because the common developer etches selectively the GaSb layer 27 .…”

“…4. This is obvious for the 60 nm mesa step sample, but it is also the case for the photolithographically fabricated contacts to the 80 nm mesa step sample, because the common developer etches selectively the GaSb layer 27 . Thus, the experimental I −V curve reflects not only inseries connected resistances of the 2D hole layer and the Nb-InAs interface, but also the interlayer charge transfer in the vicinity of the Nb contact, see Fig.…”

“…This is obvious for the 60 nm mesa step sample, where this layer is not removed. It is also the case for the photolithographically fabricated contacts to the 80 nm mesa step sample, because the common developer etches selectively the GaSb layer 27 . We study current through the Nb-InAs/GaSb junction in a four-point technique.…”

Boundary scattering in wet-etched InAs/GaSb heterostructure wires: with and without magnetic field

“…Figure 2 shows a measured magnetoresistance curve, for a 1.2 µm wide wire, with regions of field-induced boundary scattering, suppression of zero-field boundary scattering and recovery of the characteristic positive magnetoresistance of the system indicated on the plot. The positive background magnetoresistance is a consequence of the presence of both electrons and holes in this material system [20]. Shubnikov-de Haas oscillations are seen to begin at around 1 T. Also shown in bold, for comparison, is the result for an unpatterned quantum well, which shows its usual form.…”

Interfacial behaviour of polyaniline as an organic electronic material

“…The non-linearity of these curves as well as the resistance difference between pure and ammonia- Other combinations show change in electrical conductivity as a result of gate biasing but no transistor action [27]. In order to investigate the behaviour of polyaniline in such a structure we fabricated polyaniline-silica-silicon structures.…”