As a new-emerging topological crystalline insulator, SnTe exhibits exotic electronic properties such as superconductivity, and ferromagnetism. In SnTe, topological surface states exist on many surfaces, with each of them having its own unique topological surface state. Therefore, facet control of SnTe nanostructures is crucial to access specific surface property. Here, we present a facile facet control method for growing Au-catalysed SnTe nanostructures using chemical vapour deposition. Through detailed electron microscopy investigation, we found that SnTe nanostructures with different morphology can be controllablly induced: catalysts with AuSn phase induce {100} nanoplates with side facets of {010}, {021} and {111}, whereas Au5Sn catalysts result in the growth of <100> nanowires with four {100} side facets. Since {100} facets have the lowest surface energy, nanowire growth is dominated by surface-energy minimization and is thermo-dynamically controlled. In the nanoplate case, as other comparatively higher-energy facets were found, such as {021} and {111}, its growth is governed kinetically. These growth differences can be attributed to the high chemical potential in nanoplate, and the difference in catalyst status between nanoplate and nanowire: AuSn catalysts are in a liquid form while the Au5Sn catalysts are in a solid form during their growth.
AcknowledgementsThis study was financially supported by the Australian Research Council. The Australian Microscopy & Microanalysis Research Facility is acknowledged for providing characterization facilities.