ALD growth of ultra-thin Co layers on the topological insulator Sb2Te3  

作　　者：Emanuele Longo Roberto Mantovan Raimondo Cecchini Michael D.Overbeek Massimo Longo Giovanna Trevisi Laura Lazzarini Graziella Tallarida Marco Fanciulli Charles H.Winter Claudia Wiemer 

机构地区：[1]CNR-IMM,Unit of Agrate Brianza,Via C.Olivetti 2,Agrate Brianza(MB)20864,Italy [2]Universitàdegli Studi di Milano-Bicocca,Dipartimento di Scienza dei Materiali,Via R.Cozzi 55,Milano 20125,Italy [3]Department of chemistry,Wayne State University,Detroit,Michigan 48202,USA [4]CNR-IMEM,Parco Area delle Scienze 37/A,Parma 43124,Italy

出　　处：《Nano Research》2020年第2期570-575,共6页纳米研究（英文版）

基　　金：We acknowledge the MP1402-Hooking together the European research in atomic layer deposition(HERALD)COST action and the Horizon 2020 project SKYTOP"Skyrmion-Topological Insulator and Weyl Semimetal Technology"(FETPROACT-2018-01,n.824123);Efforts at Wayne State University were supported by the U.S.National Science Foundation(Grant No.CHE-1607973)and EMD Performance Materials.

摘　　要：Taking the full advantage of the conformal growth characterizing atomic layer deposition(ALD),the possibility to grow Co thin films,with thickness from several tens down to few nanometers on top of a granular topological insulator(TI)Sb2Tes film,exhibiting a quite high surface roughness(2-5 nm),was demonstrated.To study the Co growth on the Sb2Tes substrate,we performed simultaneous Co depositions also on sputtered Pt substrates for comparison.We conducted a thorough chemical-structural characterization of the Co/Sb2Tes and Co/Pt heterostructures,confirming for both cases,not only an excellent conformality,but also the structural continuity of the Co layers.X-ray diffraction(XRD)and high-resolution transmission electron microscope(HRTEM)analyses evidenced that Co on Sb2Te3 grows preferentially oriented along the[0oe]direction,following the underlying rhombohedric substrate.Differently,Co crystallizes in a cubic phase oriented along the[111]direction when deposited on Pt.This work shows that,in case of deposition of crystalline materials,the ALD surface selectivity and conformality can be extended to the definition of local epitaxy,where in-plane ordering of the crystal structure and mosaicity of the developed crystallized grains are dictated by the underlying substrate.Moreover,a highly sharp and chemically-pure Co/Sb2Tes interface was evidenced,which is promising for the application of this growth process for spintronics.

关 键 词：atomic layer deposition X-ray diffraction Co-fcc Co-hep antimony telluride metal organic chemical vapor deposition SPINTRONICS 

分 类 号：TB30[一般工业技术—材料科学与工程]