  Topological quantum computing is based on braiding of Majorana zero modes
encoding topological qubits. A promising candidate platform for Majorana zero
modes is semiconductor-superconductor hybrid nanowires. The realization of
topological qubits and braiding operations requires scalable and disorder-free
nanowire networks. Selective area growth of in-plane InAs and InSb nanowires,
together with shadow-wall growth of superconductor structures, have
demonstrated this scalability by achieving various network structures. However,
the noticeable lattice mismatch at the nanowire-substrate interface, acting as
a disorder source, imposes a serious obstacle along with this roadmap. Here,
combining selective area and shadow-wall growth, we demonstrate the fabrication
of PbTe-Pb hybrid nanowires - another potentially promising Majorana system -
on a nearly perfectly lattice-matched substrate CdTe, all done in one molecular
beam epitaxy chamber. Transmission electron microscopy shows the single-crystal
nature of the PbTe nanowire and its atomically sharp and clean interfaces to
the CdTe substrate and the Pb overlayer, without noticeable inter-diffusion or
strain. The nearly ideal interface condition, together with the strong
screening of charge impurities due to the large dielectric constant of PbTe,
hold promise towards a clean nanowire system to study Majorana zero modes and
topological quantum computing.
