Croissance épitaxiale et caractérisation champ-proche de nanostructures d’InSb pour composants électroniques avancés

At the dawn of the quantum era, which promises radically new ways of processing information, III-V semiconductors — and InSb in particular — stand out as one of the most promising material for this transition. With high electron mobility, strong spin-orbit interaction, and small effective mass, InSb exhibits ideal properties for quantum applications such as Majorana-based devices, while also offering opportunities in high-performance nanoelectronics beyond quantum computing. However, the deployment to functional devices has been hampered by the strong lattice-mismatch of InSb to conventional III-V substrates, making the growth of defect-free nanostructures challenging. This thesis investigates the Selective Area Growth (SAG) of InSb nanostructures on both lattice-matched and highly mismatched substrates using MolecularBeam Epitaxy (MBE). To enable the carrier density modulation required for quantum devices, InSb was also integrated within gated heterostructures incorporating semiconducting barriers.This thesis work dealt with the InSb growth on lattice-matched CdTe substrates at the beginning, but technological limitations constrained the quality and scalability of the InSb nanostructures. The study then shifted to GaAs (111)B substrates, where growth optimization yielded high crystal quality thin films and planar nanostructures with low defect density, as confirmed by cross-sectional Scanning Transmission Electron Microscopy (STEM) and Scanning Tunneling Microscopy (STM).Following the optimized growth on GaAs (111)B, high quality InSb thin-films and in-plane nanowires (NWs) were produced on low roughness GaInP buffer layers grown on GaAs under carefully optimized conditions. Through a structural and a morphological study, we then discussed the minor differences observed with the growth of InSb nanostructures on GaAs substrates. The final part of the thesis focused on electrical transport studies of the InSb/GaInP/GaAs:n+ heterostructure combining Hall measurements, Transfer Length Method (TLM), and Four-Probe Scanning Tunneling Microscopy (4P-STM). An effectivecharge density modulation inside the InSb nanostructures as well as a record-high electron mobility for InSb thin films grown on III-V mismatched substrate were demonstrated. A last comprehensive Scanning Tunneling Spectroscopy (STS) study revealed that precise control of surface integrity is essential to fully exploit the potential of these nanostructures.Altogether, this work establishes a scalable route to high-quality InSb nanostructures, advancing both quantum device development and high-performance III-V nanoelectronics.