XAFS studies of diluted magnetic semiconductor Mn-doped ZnSnAs2thin films on InP substrates

H Oomae,H Toyota,S Emura,N Uchitomi,H Asahi,D Niarchos,O Kalogirou,G Hadjipanayis

doi:10.1051/epjconf/20147509004

Abstract

Mn-doped ZnSnAs2 (ZnSnAs2 :Mn) thin films with 5.0 and 6.5% Mn composition were epitaxially grown by molecular beam epitaxy on InP (001) substrates. These films had a Curie temperature of 334 K, corresponding to room-temperature ferromagnetism. The local structures around Mn atoms in ZnSnAs2 :Mn were studied by analysis of the X-ray absorption fine-structure spectra. It was found that the Mn atoms substitute into Zn or Sn cation sites, and the Mn‒As bond length is 2.50 A, which is slightly smaller than the value of 2.53 A in a sphalerite (zinc-blende) ZnSnAs2 bulk crystal. The Mn‒As bond length in ZnSnAs2 :Mn is consistent with the value obtained from GaMnAs, and has a smaller value than that obtained from the zinc-blend MnAs thin films grown on a InP substrate.

Highlights

Over the last two decades, III-V based diluted magnetic semiconductors (DMSs), as well as recently developed ferromagnetic metals such as half-metallic materials, have attracted much attention for use in spintronic devices and as candidates for beyond-CMOS technology
X-ray absorption fine structure (XAFS) analysis has been effectively used for clarifying the physical properties of III-V based DMSs such as InMnAs [11], GaMnAs [12] and GaCrN [13]
We report on the local structure around the Mn atoms in the ZnSnAs2:Mn thin films grown epitaxially on InP substrates using Mn K-edge XAFS

Summary

Introduction

Over the last two decades, III-V based diluted magnetic semiconductors (DMSs), as well as recently developed ferromagnetic metals such as half-metallic materials, have attracted much attention for use in spintronic devices and as candidates for beyond-CMOS technology. GaMnAs has been extensively studied from experimental and theoretical points of view, because it is well lattice-matched with GaAs substrates and shows a relatively high Curie temperature of more than 100 K [14]. XAFS analysis has been effectively used for clarifying the physical properties of III-V based DMSs such as InMnAs [11], GaMnAs [12] and GaCrN [13]. In the case of the GaMnAs, it has been reported that the Mn atoms are substituted into the Ga sites and the Mn‒As bond (0.249‒0.250 nm) is slightly elongated from the Ga‒As bond of the GaAs lattice. In contrast to the systematic investigation of III-V based DMS thin films, there have been few opportunities to study the structural properties of II-IV-V2 based DMS thin films until now

Methods

Results

Conclusion