Epitaxial 2D MoSe2 (HfSe2) Semiconductor/2D TaSe2 Metal van der Waals Heterostructures

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• 作者：Dimitra Tsoutsou ; Kleopatra E. Aretouli ; Polychronis Tsipas ; Jose Marquez-Velasco ; Evangelia Xenogiannopoulou ; Nikolaos Kelaidis ; Sigiava Aminalragia Giamini ; Athanasios Dimoulas
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：January 27, 2016
• 年：2016
• 卷：8
• 期：3
• 页码：1836-1841
• 全文大小：383K
• ISSN：1944-8252

文摘

Molecular beam epitaxy of 2D metal TaSe₂/2D MoSe₂ (HfSe₂) semiconductor heterostructures on epi-AlN(0001)/Si(111) substrates is reported. Electron diffraction reveals an in-plane orientation indicative of van der Waals epitaxy, whereas electronic band imaging supported by first-principles calculations and X-ray photoelectron spectroscopy indicate the presence of a dominant trigonal prismatic 2H-TaSe₂ phase and a minor contribution from octahedrally coordinated TaSe₂, which is present in TaSe₂/AlN and TaSe₂/HfSe₂/AlN but notably absent in the TaSe₂/MoSe₂/AlN, indicating superior structural quality of TaSe₂ grown on MoSe₂. Apart from its structural and chemical compatibility with the selenide semiconductors, TaSe₂ has a workfunction of 5.5 eV as measured by ultraviolet photoelectron spectroscopy, which matches very well with the semiconductor workfunctions, implying that epi-TaSe₂ can be used for low-resistivity contacts to MoSe₂ and HfSe₂.