Growth and characterisation of MnSb(0 0 0 1)/InGaAs(1 1 1)A epitaxial films

P.J Mousley,C.W Burrows,M.J Ashwin,A.M Sánchez,V.K Lazarov,G.R Bell

doi:10.1016/j.jcrysgro.2018.07.006

P.J Mousley, C.W Burrows + Show 4 more

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https://doi.org/10.1016/j.jcrysgro.2018.07.006

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Abstract

MnSb layers have been grown on InxGa1-xAs(1 1 1) A virtual substrates using molecular beam epitaxy (MBE). The effects of both substrate temperature (Tsub) and Sb/Mn beam flux ratio (JSb/Mn) were investigated. The surface morphology, layer and interface structural quality, and magnetic properties have been studied for a 3 × 3 grid of Tsub and JSb/Mn values. Compared to known optimal MBE conditions for MnSb/GaAs(1 1 1) [Tsub = 415°C,JSb/Mn = 6.5], a lower substrate temperature is required for sharp interface formation when growing MnSb on In0.48Ga0.52As(1 1 1) A [Tsub = 350°C,JSb/Mn = 6.5]. At high flux ratio (JSb/Mn = 9.5) elemental Sb is readily incorporated into MnSb films. At higher substrate temperatures and lower flux ratios, (In,Ga) Sb inclusions in the MnSb are formed, as well as MnAs inclusions within the substrate. The Sb and (In,Ga) Sb inclusions are epitaxial, while MnAs inclusions are endotaxial, i.e. all have a crytallographic relationship to the substrate and epilayer. MBE optimisation towards different device structures is discussed along with results from a two-stage growth scheme.

Highlights

The epitaxial combination of magnetic and semiconducting materials can underpin new spintronic device technologies with great potential for lowenergy computation and data storage [1]
In this paper we present a detailed molecular beam epitaxy (MBE) growth study aimed at gaining a better understanding of this material system
A full sample set across the 3×3 grid of growth conditions was grown using a single-stage growth methodology, where the substrate temperature was held constant throughout MnSb deposition

Summary

Introduction

The epitaxial combination of magnetic and semiconducting materials can underpin new spintronic device technologies with great potential for lowenergy computation and data storage [1]. Preprint submitted to Journal Name are the spin valve and the spin field-effect transistor For the latter in particular, Inx Ga1−x As conducting channels are attractive, this material having high electron mobility and electron g-factor [2, 3]. Transition metal monopnictides are materials that may be ideal for spintronic applications in combination with III-V semiconductor structures since they can be grown epitaxially by conventional molecular beam epitaxy (MBE) and have a wide variety of controllable magnetic properties. The cubic B3 polymorph of MnSb is predicted to have robust half-metallicity (100% spin polarization at the Fermi level) even at room temperature [8], with high spin polarisation retained at III-V interfaces [20]. (SEM), scanning transmission electron microscopy with energy dispersive Xray spectroscopy (STEM and EDX), X-ray diffraction (XRD) and vibrating sample magnetometry (VSM)

Experimental details

Results

SEM and AFM

Discussion and conclusions