Controlling Crystal Structure and Oxidation State in Molybdenum Nitrides through Epitaxial Stabilization

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• 作者：Hongmei Luo ; Guifu Zou ; Haiyan Wang ; Joon Hwan Lee ; Yuan Lin ; Huisheng Peng ; Qianglu Lin ; Shuguang Deng ; Eve Bauer ; T. Mark McCleskey ; Anthony K. Burrell ; Quanxi Jia
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：September 15, 2011
• 年：2011
• 卷：115
• 期：36
• 页码：17880-17883
• 全文大小：773K
• 年卷期：v.115,no.36(September 15, 2011)
• ISSN：1932-7455

文摘

Epitaxial molybdenum nitride films with different crystal structures and chemical compositions were successfully synthesized by a chemical solution deposition technique. Hexagonal MoN was stabilized on c-cut sapphire (Al₂O₃) but cubic Mo₂N on (001) SrTiO₃ even though exactly the same Mo-polymer precursor solution and the processing parameters (such as the annealing temperature and environment) were used. Both X-ray diffraction and high-resolution transmission electron microscopy confirmed the growth of epitaxial molybdenum nitride films with an epitaxial relationship between the film and the substrate as (0001)_MoN||(0001)_Al2O3 and [101虆0]_MoN||[112虆0]_Al2O3 for MoN on c-cut Al₂O₃ and (001)_Mo2N||(001)_STO and [111]_Mo2N||[111]_STO for Mo₂N on SrTiO₃. The formation of epitaxial molybdenum nitride films with different oxidation states resulted in very different electrical properties: a superconducting transition temperature of 12 K for MoN, whereas it was 4.5 K for Mo₂N.