The Mn site in Mn-doped Ga-As nanowires: an EXAFS study

TL;DR

This study uses EXAFS to analyze the local atomic environment of Mn in Mn-doped GaAs nanowires, revealing non-substitutional bonding and the formation of MnAs-like phases or intermetallic compounds.

Contribution

It provides detailed atomic-level insights into Mn bonding environments in GaAs nanowires, highlighting differences based on doping methods.

Findings

Mn bonds with As but is not substitutionally incorporated

Mn in Mn-induced wires shows disordered Mn-As bonds similar to MnAs phases

Presence of Mn-Au intermetallic compounds in Au-seeded nanowires

Abstract

We present an EXAFS study of the Mn atomic environment in Mn-doped GaAs nanowires. Mn doping has been obtained either via the diffusion of the Mn used as seed for the nanowire growth or by providing Mn during the growth of Au-induced wires. As a general finding, we observe that Mn forms chemical bonds with As but is not incorporated in a substitutional site. In Mn-induced GaAs wires, Mn is mostly found bonded to As in a rather disordered environment and with a stretched bond length, reminiscent of that exhibited by MnAs phases. In Au-seeded nanowires, along with stretched Mn-As coordination we have found the presence of Mn in a Mn-Au intermetallic compound.