The development of a materials platform that exhibits both superconducting and semiconducting properties is an important endeavour for a range of emerging quantum technologies. We investigate the formation of superconductivity in nanowires fabricated with silicon-on-insulator (SOI). Aluminium from deposited contact electrodes is found to interdiffuses with the Si nanowire structures to form an Al-Si alloy along the entire length of the predefined nanowire device over micron length scales at temperatures well below that of the Al-Si eutectic. The resultant transformed nanowire structures are layered in geometry with a continuous Al-Si alloy wire sitting on the buried oxide of the SOI and a residual Si cap sitting on top of the wire. The phase transformed material is conformal with any predefined device patterns and the resultant structures are exceptionally smooth-walled compared to similar nanowire devices formed by silicidation processes. The superconducting properties of a mesoscopic AlSi ring formed on a SOI platform are investigated. Low temperature magnetoresistance oscillations, quantized in units of the fluxoid, h/2e, are observed.
@article{arxiv.2207.05343,
title = {Phase transformation-induced superconducting aluminium-silicon alloy rings},
author = {B. C. Johnson and M. Stuiber and D. L. Creedon and A. Berhane and L. H. Willems van Beveren and S. Rubanov and J. H. Cole and V. Mourik and A. R. Hamilton and T. L. Duty and J. C. McCallum},
journal= {arXiv preprint arXiv:2207.05343},
year = {2025}
}