Ultra-high-vacuum 3D printing for mesoscopic components

Very precise control of semiconductor crystals at the nanometer scale has become essential for the manufacture of advanced electronic components or for certain quantum technologies. In this context, nanowires based on III-V semiconductors with low electronic mass have particularly interesting properties. However, the fabrication of electronic circuits based on such objects requires their implementation in complex architectures (cross-networks) in a robust and reliable way while preserving their intrinsic properties.

In this context, selective molecular beam epitaxy allows the elaboration of nanocrystals precisely localized on the substrate surface thanks to the use of a dielectric mask.  In this work*, we show how this growth method can be used to fabricate planar nanowires composed of an InGaAs core and an InP shell. A second step of selective growth also allows us to adorn these nanowires with highly doped contact zones to be able to fabricate transistors whose source/drain spacing can be adjusted down to less than 30 nm. With this bottom-up fabrication method, which avoids any semiconductor etching step, components with different lengths have been fabricated. They have made it possible to study the electron transport properties in nanowires down to very low temperatures in a transport regime where the electrons are likely to be ballistic.

* « Gate length dependent transport properties of in-plane core-shell nanowires with raised contacts », A.Bucamp, C.Coinon, D.Troadec, S.Lepilliet, G.Patriarche, X.Wallart and L.Desplanque, Nano Research 13, p61–66 (2020) https://doi.org/10.1007/s12274-019-2572-8