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Electron Diffraction Study Of Cuinse2 (Te2) Superlattice Films Phase

Nuriyev Mubariz Asker

Abstract


This article presents the results of conditions of studies CuInSe2(Te2) films formation with varying substructure.

A sample of this massive crystal  was evaporated from tungsten conical helice, the distance between the source and the condensing plane was 7cm. The substrate temperature was increased in steps of 50K. The substrate heated to 773 K was cooled spontaneously to room temperature in vacuum. The calculated thickness of the films in all cases was about 50 nm. We have discussed the issue of forming films of CuInSe2(Te2) to condensate produced on substrates of single-crystal chips of fresh rock salt at different temperatures.                                                                                                     

We also researched conditions for obtaining films of CuInSe2(Te2), the elucidation of  the single crystal layers’ conditions formation, as well as  the evaluation of these structures’ perfection degree.      The observed superstructure phase in epitaxial films of CuInTe2 is oriented on the plane (100) paralell (100) face of KBr. In the case of epitaxial growth on a KBr CuInTe2 one unit cell superstructure phase is accompanied with two substrate cells. The relative mismatch mating crystalline grid is about 2%. The established contact elementary cell lattice between the period of grating superstructure of  CuInTe2 and  the initial grating was а=аоÖ5; с=соÖ5.      

The films produced in the range of substrate temperatures  from 573K to 623K are the mixture of mono and polycrystalline condensate. Thus oriented single crystals of the plane (001) CuInSe2 is paralell to (001) NaCl. The grain sizes in the condensates obtained on substrates located at temperatures 473-673K vary in the range of 20-40nm.

Thus, CuInSe2 epitaxial growth on the surface of a single crystal’s natural cleavage  NaCl can flow sufficiently to form a perfect single crystal CuInSe2 ~ 773K substrate temperature because the difference between the periods "a" and lattices NaCl mismatch is only 2.6%. Period “c” CuInSe2 ≈ 2a NaCl.


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