Two-dimensional semiconductor HfSe2 and MoSe2/HfSe2 van der Waals heterostructures by molecular beam epitaxy

• DOI: 10.1063/1.4917422
• Publication Date: 2015-04-08T18:58:50Z
• Authors: K. E. Aretouli; P. Tsipas; D. Tsoutsou; J. Marquez-Velasco; E. Xenogiannopoulou; S. A. Giamini; E. Vassalou; N. Kelaidis; A. Dimoulas
• Keywords: Band offset; Surface reconstruction

Using molecular beam epitaxy, atomically thin 2D semiconductor HfSe2 and MoSe2/HfSe2 van der Waals heterostructures are grown on AlN(0001)/Si(111) substrates. Details of the electronic band structure imaged by in-situ angle resolved photoelectron spectroscopy indicating a high quality epitaxial layer. High-resolution surface tunneling microscopy supported first principles calculations provides evidence an ordered Se adlayer, which may be responsible for reduction measured workfunction compared to theoretical predictions. The latter minimizes difference between MoSe2 layers resulting in small valence offset only 0.13 eV at heterointerface weak type II alignment.