A reliable route to the deterministic fabrication of impurity ion donors in silicon is required to advance quantum computing architectures based upon such systems. This paper reports the ability to dope isotopically-defined unique (121Sb123Sb) clusters into silicon with measured detection efficiencies of 94% being obtained. Atomically resolved imaging of the doped clusters reveals a Sb-to-Sb separation of ~2 nm post-implantation, thus indicating suitability to form coupled qudit systems. The method used is fully compatible with integration into processing that includes pre-enrichment of the silicon host to < 3ppm 29Si levels. As such, we present a potential pathway to the creation of scaled qudit arrays within silicon platforms for quantum computing.
@article{arxiv.2509.03243,
title = {Isotopically Selected Single Antimony Molecule Doping},
author = {Mason Adshead and Maddison Coke and Evan Tillotson and Kexue Li and Sam Sullivan-Allsop and Ricardo Egoavil and William Thornley and Yi Cui and Christopher M Gourlay and Katie L Moore and Sarah J Haigh and Richard J Curry},
journal= {arXiv preprint arXiv:2509.03243},
year = {2025}
}