Molecular beam epitaxial growth of ultrathin buried metal layers: (Al,Ga)As/NiAl/(Al,Ga)As heterostructures Available to Purchase

We report the first growth of epitaxial NiAl metallic layers buried within monocrystalline GaAs/AlAs/NiAl/AlAs/GaAs heterostructures deposited entirely within a molecular beam epitaxy growth chamber. The layer growth sequence is monitored by reflection high‐energy electron diffraction. Cross‐sectional transmission electron microscopy shows that the metal layers and the III‐V overgrowth are monocrystalline and of high quality. Thin, buried NiAl layers over the entire thickness range investigated (3–100 nm) are electrically continuous (69 μΩ cm at 3 nm). The heterostructures formed by this process can be used for the fabrication of thin‐metal buried‐layer devices utilizing ballistic transport or quantum mechanical tunneling across thin metal bases.