III-V Semiconductor-Hybrid Systems
III-V semiconductors containing group III and V elements, such as GaAs or AlGaAs, are often the material of choice if it comes to the exploration of quantum effects in semiconductor nanostructures.
Prominent examples are the quantum Hall effect, quantized conductance, or single electron transport. In addition, III-V semiconductors are also very attractive for fast and ultra-low power consumption electronic circuits. I big advantage of this material class is the large variety of material parameters, i.e. electron band gap or effective mass. While fabricating heterostructures composed of different planar layers of III-V materials is a well-established technique, recent developments point towards a so-called bottom-up approach. Here, the nanostructures, e.g. semiconductor nanowires, are grown directly without elaborate lithography steps. Even more fascinating opportunities arise if these III-V nanostructures are combined in-situ with other materials such as ferromagnets, superconductors, normal metals, or dielectrics. The in-situ fabrication ensures that clean interfaces are formed, which are crucial for a reliable operation of device structures. As an example, in-situ prepared nanowire-superconductor hybrid structures can be employed to realize so-called gatemon quantum bits, i.e. superconducting quantum bits based on gate-controlled nanowire Josephson junctions. On an even more fundamental level these hybrid structures are also considered as platform to realize Majorana fermions.
InAs Nanowire Nb Josephson Junction
Electron microscopic image of InAs nanowire field effect transistors with multiple bottom gates
