4 research outputs found
Single-crystalline PbTe film growth through reorientation
Heteroepitaxy enables the engineering of novel properties, which do not exist
in a single material. Two principle growth modes are identified for material
combinations with large lattice mismatch, Volmer-Weber and Stranski-Krastanov.
Both lead to the formation of three-dimensional islands, hampering the growth
of flat defect-free thin films. This limits the number of viable material
combinations. Here, we report a distinct growth mode found in molecular beam
epitaxy of PbTe on InP initiated by pre-growth surface treatments. Early
nucleation forms islands analogous to the Volmer-Weber growth mode, but film
closure exhibits a flat surface with atomic terracing. Remarkably, despite
multiple distinct crystal orientations found in the initial islands, the final
film is single-crystalline. This is possible due to a reorientation process
occurring during island coalescence, facilitating high quality heteroepitaxy
despite the large lattice mismatch, difference in crystal structures and
diverging thermal expansion coefficients of PbTe and InP. This growth mode
offers a new strategy for the heteroepitaxy of dissimilar materials and expands
the realm of possible material combinations
Selective Area Growth of PbTe Nanowire Networks on InP
Hybrid semiconductor–superconductor nanowires are promising candidates as quantum information processing devices. The need for scalability and complex designs calls for the development of selective area growth techniques. Here, the growth of large scale lead telluride (PbTe) networks is introduced by molecular beam epitaxy. The group IV-VI lead-salt semiconductor is an attractive material choice due to its large dielectric constant, strong spin-orbit coupling, and high carrier mobility. A crystal re-orientation process during the initial growth stages leads to single crystalline nanowire networks despite a large lattice mismatch, different crystal structure, and diverging thermal expansion coefficient to the indium phosphide (InP) substrate. The high quality of the resulting material is confirmed by Hall bar measurements, indicating mobilities up to 5600 cm2 (Vs)−1, and Aharonov–Bohm experiments, indicating a low-temperature phase coherence length exceeding 21 µm. Together, these properties show the high potential of the system as a basis for topological networks.</p
Growth of PbTe nanowires by molecular beam epitaxy
Advances in quantum technology may come from the discovery of new materials
systems that improve the performance or allow for new functionality in
electronic devices. Lead telluride (PbTe) is a member of the group IV-VI
materials family that has significant untapped potential for exploration. Due
to its high electron mobility, strong spin-orbit coupling and ultrahigh
dielectric constant it can host few-electron quantum dots and ballistic quantum
wires with opportunities for control of electron spins and other quantum
degrees of freedom. Here, we report the fabrication of PbTe nanowires by
molecular beam epitaxy. We achieve defect-free single crystalline PbTe with
large aspect ratios up to 50 suitable for quantum devices. Furthermore, by
fabricating a single nanowire field effect transistor, we attain bipolar
transport, extract the bandgap and observe Fabry-Perot oscillations of
conductance, a signature of quasiballistic transmission