Defect engineering of the electronic transport through cuprous oxide interlayers

TL;DR

This study uses first-principles calculations to explore how defects and doping affect electronic conductance in Cu2O interlayers between gold electrodes, revealing defect types that significantly enhance transport.

Contribution

It provides a detailed analysis of defect and doping effects on conductance in Cu2O junctions, highlighting the role of bulk-like defects and specific dopants in improving electronic transport.

Findings

Bulk-like defects enhance conductance except O vacancies and Cl substitution.

N and Cl doping increase conductance, consistent with experiments.

Frenkel defects lead to very high conductance.

Abstract

The electronic transport through Au-(Cu$_{2}$O)$_n$-Au junctions is investigated using first-principles calculations and the nonequilibrium Green's function method. The effect of varying the thickness (i.e., $n$) is studied as well as that of point defects and anion substitution. For all Cu$_{2}$O thicknesses the conductance is more enhanced by bulk-like (in contrast to near-interface) defects, with the exception of O vacancies and Cl substitutional defects. A similar transmission behavior results from Cu deficiency and N substitution, as well as from Cl substitution and N interstitials for thick Cu$_{2}$O junctions. In agreement with recent experimental observations, it is found that N and Cl doping enhances the conductance. A Frenkel defect, i.e., a superposition of an O interstitial and O substitutional defect, leads to a remarkably high conductance. From the analysis of the defect formation energies, Cu vacancies are found to be particularly stable, in agreement with earlier experimental and theoretical work.