| Description |
Conducting lines of tungsten can be fabricated on a substrate by decomposition of an organometallic gas using a focused ion or electron beam. Amorphous tungsten obtained by ion beam-induced deposition (IBID) has high superconducting critical temperature (4 K) and critical field (9 T) compared to bulk crystals (only 10 mK). It is a useful technique for the direct writing of electrodes and contacting nanostructures for the study of proximity-induced superconductivity.
However, nanostructures may be damaged or doped on exposure to the ion beam, and an alternate method is to use electron beam-induced deposition (EBID). We have observed superconductivity in nanowires realized by EBID - an experimental challenge so far. We will also present the application of these techniques for the study of superconducting devices of graphene and bismuth nanowires. Critical current oscillations are observed in devices of bismuth as a function of the magnetic field and this phenomenon will be discussed in relation to the electronic properties of the nanowire surface states. |