Abstract
Fabrication of Si-Ge nanowire heterostructures offers great design flexibility in device applications, provided the interfaces are defect-free and compositionally abrupt. We use in-situ transmission electron microscopy to study nanowire growth, and find that abrupt Si-Ge interfaces can be fabricated in nanowires by a growth method that uses a solid AlAu2 catalyst. Growth of uniform segments of SiGe alloy in Si nanowires with sharp interfaces can also be realized using this method. We present in-situ measurements of nanowire growth kinetics and discuss the strain distribution and thermal stability in Si/Ge and Si/Ge/Si nanowire junction structures.