GeVn complexes for silicon-based room-temperature single-atom nanoelectronics

TL;DR

This study uses advanced computational methods to analyze germanium-vacancy complexes in silicon, revealing their electronic states and potential for room-temperature single-atom nanoelectronics.

Contribution

It provides detailed first-principles characterization of GeVn complexes, highlighting their electronic states and localization, advancing their application in silicon-based nanoelectronics.

Findings

GeV complexes exhibit two deep excited states in the band gap.

Electronic states are localized within approximately 0.45 nm.

GeVn complexes are promising for room-temperature single-atom devices.

Abstract

We characterize germanium-vacancy GeVn complexes in silicon using first-principles Density Functional Theory calculations with screening-dependent hybrid functionals. We report on the local geometry and electronic excited states of these defects, including charge transition levels corresponding to the addition of one or more electrons to the defect. Our main theoretical result concerns the GeV complex, which we show to give rise to two excited states deep in the gap, at -0.51 and -0.35 eV from the conduction band, consistently with the available spectroscopic data. The adopted theoretical scheme, suitable to compute a reliable estimate of the wavefunction decay, leads us to predict that such states are associated to an electron localization over a length of about 0.45 nm. By combining the electronic properties of the bare silicon vacancy, carrying deep states in the band gap, with the spatial controllability arising from single Ge ion implantation techniques, the GeVn complex emerges as a suitable ingredient for silicon-based room-temperature single-atom devices.