Atuchin, Victor V.

Bereznaya, Svetlana A.

Korotchenko, Zoya V.

Novikov, Vladimir A.

Redkin, R. A.

Sarkisov, Sergey Yu.

English

Tomsk State University Repository

 175 FORMATION OF NATIVE OXIDE CRYSTALLITES ON THE GaSe(001) CLEAVED SURFACE Bereznaya S.A.1, Korotchenko Z.V.1, Novikov V.A.2, Red’kin R.A.1, Sarkisov S.Yu.1, Atuchin V.V.1,3,4 1Functional Electronics Laboratory, Tomsk State University, Tomsk, Russia 2Nanolectronics and Nanophotonics Laboratory, Tomsk State University, Tomsk, Russia 3Laboratory of Optical Materials and Structures, Institute of Semiconductor Physics, SB RAS, Novosibirsk, Russia 4Laboratory of Semiconductor and Dielectric Materials, Novosibirsk State University, Novosibirsk, Russia, atuchin@isp.nsc.ru Gallium selenide is a well-known nonlinear optical crystal for IR and terahertz ranges. Besides many advantages this layered material possesses low mechanical hardness and high density of structural defects. Another problem is that GaSe(001) cleaved surface readily oxidizes and foreign chemical compounds form by the interaction with the humid atmosphere components. This reduces the stability of optical properties of the GaSe elements. On this reason, it is interesting to study the temporal evolution of the oxide formation process and influence of environmental conditions which can be present at optical experiments. In our work, we study the evolution of GaSe native oxide formation using atomic-force microscopy (AFM) methods. It was found that the growth of oxide film is accompanied by work function increase. This increase saturates after several hours exposition.   AFM pattern of GaSe surface morphology Distribution of contact potential difference The illumination by 1 mW laser at 650 nm wavelength stimulates the oxidation process. Continuous illumination changes the work function by 1 eV  176 that is 2 times higher than that obtained without laser irradiation. It can be supposed that oxide formation occurs at edge dislocations. The surface density of oxide formation centers is about 1·106 cm-2 that is close to dislocation density typical for GaSe. “Ti49,3Ni 50,7 - ALLOY VT6” BIMETALLIC COMPOSITE OBTAINED BY EXPLOSION WELDING Rubanik V.V.1,2, Belyaev S.P.3, Resnina N.N.3, Rubanik V.V. jr.1,2 1Vitebsk State Technological University, Vitebsk, Belarus, iakustika@mail.ru 2Institute of Technical Acoustics of NAS of Belarus, Vitebsk, Belarus 3Saint Petersburg State University, Saint Petersburg, Russia The investigations of temperature and sequence of thermoelastic martensitic transformations in “Ti49,3Ni 50,7 - alloy VT6” bimetallic composite produced by explosion welding are carried out. The composite consists of two layers: one of them is NiTi layer with excess of nickel exhibits shape memory effect and plays the role of an actuator in the composition, and the second one is titanium alloy performing the role of an elastic member. 0 20 40 60 80 100020406080100 C, %L, mkm Ti Ni Al V Fig.1. The microstructure of the transition zone in “Ti49,3Ni 50,7 - alloy VT6” bimetallic composite and the distribution of chemical elements along the cross-section It is found that the martensitic transformations in the bimetallic composite are developed according the following scheme: B2 → B19'. The significant increase in reverse martensitic transformation temperatures takes place after the explosion welding, while the latent heat of the phase transition decreases, which is associated with the acquired strong plastic deformation during the 

Formation of native oxide crystallites on the GaSe(001) cleaved surface

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Formation of native oxide crystallites on the GaSe(001) cleaved surface

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