Room temperature donor incorporation for quantum devices: arsine on germanium

TL;DR

This study demonstrates that arsine can fully incorporate arsenic donors into germanium at room temperature, enabling scalable atomic-scale quantum devices with improved properties over silicon-based systems.

Contribution

It introduces a novel room temperature doping method using arsine on germanium, overcoming limitations of traditional phosphorus doping in silicon.

Findings

Arsine fully incorporates arsenic into germanium at room temperature.

This method enables scalable, deterministic placement of donor atoms.

Germanium's electronic properties are enhanced for quantum device applications.

Abstract

Germanium has emerged as an exceptionally promising material for spintronics and quantum information applications, with significant fundamental advantages over silicon. However, efforts to create atomic-scale devices using donor atoms as qubits have largely focussed on phosphorus in silicon. Positioning phosphorus in silicon with atomic-scale precision requires a thermal incorporation anneal, but the low success rate for this step has been shown to be a fundamental limitation prohibiting the scale-up to large-scale devices. Here, we present a comprehensive study of arsine (AsH$_3$) on the germanium (001) surface. We show that, unlike any previously studied dopant precursor on silicon or germanium, arsenic atoms fully incorporate into substitutional surface lattice sites at room temperature. Our results pave the way for the next generation of atomic-scale donor devices combining the superior electronic properties of germanium with the enhanced properties of arsine/germanium chemistry that promises scale-up to large numbers of deterministically-placed qubits.