Ioffe Physical-Technical Institute RAS

Solid State Physics Branch. Laboratory of Solid State Spectroscopy.

Main directions of works
Members of the group
Source of financings of work
Main work instrument
Main publications
Contact person
Postal address

Main directions of works:

Studing of processes of growth and properties of dielectric layers
of nano-structures based on fluoride, and also
monocrystalline ferromagnetic films.
Semiconductors. A surface and thin films.
Microstructures.


Members of the group:
Nickolai S.Sokolov - chief;
Sergey V.Gastev - researcher;
Nickolai L.Yakovlev - researcher;
Alexander G.Banchikov - researcher;
Marina M.Moiseeva - researcher;
Andrey Yu.Hil`ko - researcher;
Sergei M.Sutunin - researcher;

Source of financings of work: The works are carried out at support of Russian Foundation for Basic Research, project #98-02-18251, and program of a science "Physics solid-state nano-structures", project №97-2018.

Main work instrument: P4-SPM-MDT

Main publications:
1. N.S.Sokolov, J.C.Alvarez, S.V.Gastev, Yu.V.Shusterman, Y.Itoh, J.Harada, R.M.Overney. High quality CaF₂ layers on Si(111) with type A epitaxial relation at the interface // Journal of Crystal Growth 1996, 169 (1), 40-50.
Abstract: The crystal perfection of MBE-grown CaF₂/Si(111) heterostructures with type-A of epitaxial relations at the CaF₂/Si(111) interface was investigated. A number of research methods, including X-ray and electron diffraction, photoluminescence of rare earth ions and atomic force microscopy, was applied. It was shown that the two-step low temperature growth with an intermediate annealing at 850°C is an efficient way to obtain type-A pseudomorphic sructures with a tickness of CaF₂ film up to 50 nm.

2. N.S.Sokolov, J.C.Alvarez, Yu.V.Shusterman, N.L.Yakovlev, R.M.Overney, Y.Itoh, I.Takshashi, J.Harada Structural transformations at CaF₂/Si(111) interface // Applied Surface Science, 1996, 104/105, p.402-408.
Abstract: Transformations of the atomic structure of CaF₂/Si(111) interface during annealing have been studied by reflection high energy electron diffraction (RHEED) and X-ray crystal trancation rod (CTR) scattering. The surface morphology after annealing has been studied by atomic force microscopy (AFM). A conversion of epitaxial relation of the film with respect to the substrate, from type-A (nonrotated) to type-B (with the axes of the film rotated by 180° around the interface normal), was monitored by RHEED during annealing of the films. On the basis of RHEED, CTR and AFM data, a model of the conversion is suggested. In addition, a spontaneous transition of type-B interface formed during the growth to the interface with another atomic arrangment has been studied with CTR. The possible role of point defect motion in CaF₂ film during this transition is discussed.

3. N.S.Sokolov, J.C.Alvarez, Yu.V.Shusterman, N.L.Yakovlev, R.M.Overney, Y.Itoh, I.Takahashi, J.Harada Structural transformations at CaF₂/Si(111) interface // International Conference on the Formation of Semiconductor Interfaces (ICFSI-5). 1995. 136, Princeton, USA, June 1995.
Abstract: As far as each Si and CaF₂ (111) surfaces are terminated by one kind of atoms, the resulting interface structure could be expected relatively simple. However different types of the interfaces were observed and one of the intrigue problems is the existence of CaF₂/Si(111) interfaces non-rotated (type A) and rotated by 180° around the (111) plane normal (type B). Here we demonstrate the first 'in stu' observation of type A to type B interface conversion and study of the interface atomic arrangments.

Contact person: Nickolai S.Sokolov
Tel.: ++7 (812) 247-6411
Tel.: ++7 (812) 552-1754 (home)
Fax: ++7 (812) 247-8640
E-mail: nsokolov@fl.ioffe.rssi.ru

Postal address: 194021 St.-Petersburg, Physical Technical Institute, Polutechnicheskaia str., build.#26, Sokolov N.