VAN-DER-WAALS HETEROEPITAXY OF LAYERED SNSE2 ON SI(111) AND BI2SE3(0001) SURFACES
S.A. Ponomarev1,2, K.E. Zakhozhev1,2, D.I. Rogilo1, N.N. Kurus1, D.V. Sheglov1, A.G. Milekhin1, A.V. Latyshev1,2
1Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
Keywords: van-der-Waals heteroepitaxy, silicon, selenium, metal chalcogenides, BiSe, surface, SnSe
Abstract
Layered SnSe2 50 and 30 nm thick films are grown using in situ reflection electron microscopy on Si(111) and Bi2Se3(0001) substrates. The growth of films proceeds by a multilayer mechanism with the formation of pronounced mounds. The height of the atomic steps is measured by atomic force microscopy (AFM) and amounts to 0.6 nm, which corresponds to the thickness of the SnSe2 layer. The ex situ AFM image of the SnSe2 film grown on Si(111) shows a high concentration of screw dislocations in the film (~12 μm-2) and the presence of domains with triangular step faceting having two types of orientation with respect to the substrate. It has been found that the SnSe2 growth on the single crystal Bi2Se3(0001) surface occurs with the formation of hexagonal-faceted mounds equally oriented with respect to the substrate. The mounds are formed by a multilayer mechanism both in the places where screw dislocations come to the surface and due to periodic nucleation of 2D islands on the highest terraces. The sizes of the highest terraces are up to 1 μm. The spectra characteristics of the films are obtained using the Raman scattering method on both substrates and correspond to the 1T-SnSe2 phase in both cases.
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