Structure of Nanowires Fabricated by Electron Beam Induced Deposition to Connect Self-Assembled Quantum Structures

Abstract

Nanowires for measuring the electronic transport property of a self-assembled quantum dot and a quantum ring were fabricated by electron beam induced deposition (EBID), and cross-sectional transmission electron microscopy (TEM) observations were conducted for the first time for the nanowires. TEM observations revealed that an amorphous layer existed between the substrate and the W deposit, showing a low W deposition rate at the early stage of deposition, and confirmed that the layer was an amorphous carbon layer. The layer growth mechanism was discussed using a phenomenological theory considering two different precursors and assuming one of the precursors covers the entire surface initially. It was shown that the layer manner growth happens in a wide range of parameters. From high-resolution TEM, obvious signs of irradiation damage during the deposition were not observed, and the amorphous layer thickness was about 5 nm, which should not affect much transport property measurement, indicating that EBID is quite promising for nanowire fabrication for transport measurements of a single self-assembled nanostructure.