Valence Band Control of Metal Silicide Films via Stoichiometry

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• 作者：Frank Streller ; Yubo Qi ; Jing Yang ; Filippo Mangolini ; Andrew M. Rappe ; Robert W. Carpick
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2016
• 出版时间：July 7, 2016
• 年：2016
• 卷：7
• 期：13
• 页码：2573-2578
• 全文大小：404K
• 年卷期：0
• ISSN：1948-7185

文摘

The unique electronic and mechanical properties of metal silicide films render them interesting for advanced materials in plasmonic devices, batteries, field-emitters, thermoelectric devices, transistors, and nanoelectromechanical switches. However, enabling their use requires precisely controlling their electronic structure. Using platinum silicide (Pt_xSi) as a model silicide, we demonstrate that the electronic structure of Pt_xSi thin films (1 ≤ x ≤ 3) can be tuned between metallic and semimetallic by changing the stoichiometry. Increasing the silicon content in Pt_xSi decreases the carrier density according to valence band X-ray photoelectron spectroscopy and theoretical density of states (DOS) calculations. Among all Pt_xSi phases, Pt₃Si offers the highest DOS due to the modest shift of the Pt_5d manifold away from the Fermi edge by only 0.5 eV compared to Pt, rendering it promising for applications. These results, demonstrating tunability of the electronic structure of thin metal silicide films, suggest that metal silicides can be designed to achieve application-specific electronic properties.