Superconducting molybdenum nitride epitaxial thin films deposited on MgO and α-Al2O3 substrates by molecular beam epitaxy
Superconducting molybdenum nitride epitaxial thin films deposited on MgO and α-Al2O3 substrates by molecular beam epitaxy
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DOI：
10.1016/j.apsusc.2006.06.024
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发表时间：
2006-12-30
影响因子：
6.7
通讯作者：
Yamanaka, Shoji
中科院分区：
文献类型：
--
作者：
Inumaru, Kei;Baba, Kazuya;Yamanaka, Shoji
采用分子束外延技术，在氮基辐照下，在MgO(001)和α-Al_2O_3(001)衬底上生长了氮化钼Mo2Nx薄膜。X射线光电子能谱分析表明，薄膜的成分随生长温度的不同而在Mo2N1.4-Mo2N2.8范围内变化。在973K下沉积的薄膜在两种衬底上都得到了结晶良好的薄膜。X射线衍射仪的高分辨率倒易空间图表明，在923K的温度下，在氧化镁衬底上外延生长了富氮的γ-Mo2N相(组成：Mo2N1.4)，具有轻微的四方形变(a=0.421，c=0.418 nm)，以适应氧化镁晶格(a=0.421 nm)。在α-Al_2O_3(001)衬底上，在973K下生长了(111)面平行于衬底表面的富氮γ-Mo2N(Mo2N1.8)。用多轴衍射仪进行的X射线衍射分析表明，α-Al_2O_3(001)上的γ-Mo2N具有轻微的菱面体形变(a=0.4173(2)和α=90.46(3)度)。在973K下，在氧化镁和α-Al_2O_3(001)衬底上生长的薄膜在2.8-3K以下具有超导电性。(C)2006爱思唯尔B.V.保留所有权利。
Molybdenum nitride Mo2Nx films were grown on MgO(001) and on alpha-Al2O3(001) substrates by molecular beam epitaxy under nitrogen radical irradiation. X-ray photoelectron spectroscopy revealed that the composition of the film varied in the range of Mo2N1.4-Mo2N2.8 depending on the growth temperature. The deposition at 973 K gave well-crystallized films on both substrates. The high-resolution reciprocal space mapping by X-ray diffraction showed that the nitrogen-rich gamma-Mo2N crystalline phase (the composition: Mo2N1.4) was epitaxially grown on MgO at 923 K with a slight tetragonal distortion (a = 0.421 and c = 0.418 nm) to fit the MgO lattice (a = 0.421 nm). On alpha-Al2O3(0 0 1), nitrogen-rich gamma-Mo2N (Mo2N1.8) was grown at 973 K with (111) planes parallel to the substrate surface. X-ray diffraction analysis with a multi-axes diffractometer revealed that the gamma-Mo2N on alpha-Al2O3(001) had a slight rhombohedral distortion (a = 0.4173(2) and alpha = 90.46(3)degrees). Superconductivity was observed below 2.8-3 K for the films grown at 973 K on MgO and on alpha-Al2O3(001). (c) 2006 Elsevier B.V. All rights reserved.