Характеристика наноструктурованих включень In6Se7 у шаруватих кристалах α-In2Se3 аналітичними методами рентгенівської дифрактометрії

• Datum: 2022
• Hauptverfasser: Drapak, S.I., Gavrylyuk, S.V., Khalavka, Y.B., Fotiy, V.D., Fochuk, P.M., Fediv, O.I.
• Format: Artikel
• Sprache: English; Ukrainian
• Veröffentlicht: Publishing house "Academperiodika" 2022
• Schlagworte: шаруватi кристали In2Se3; мiкроструктура; включення нанокристалiтiв; композити; аналiтичнi методи рентгенiвської дифрактометрiї
• Online Zugang: https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2021393
• Назва журналу: Ukrainian Journal of Physics

As follows from the X-ray structural analysis, In2Se3 crystals grown from the stoichiometric melt using the Bridgman method turned out inhomogeneous: some of the samples obtained from the same ingot contained only the hexagonal α-In2Se3 phase, whereas inclusions of the In6Se7 crystalline phase were found in the others. The presence of narrower-band-gap semiconductor inclusions in the α-In2Se3 matrix gives rise to the current instability with Z- and N-shaped current-voltage characteristics (CVCs) of the samples; at the same time, single-phase samples demonstrate linear CVCs. Several analytical methods of X-ray diffraction (XRD) analysis, which were applied to characterize the structure of In6Se7 inclusions, testified to the presence of compressive strains in them. It is shown that, owing to the action of compressive strains, the average sizes of In6Se7 crystallites determined using the modified Scherrer, Size-Strain Plot, and Halder–Wagner methods coincide with an accuracy higher than 1% and equal about 26.5 nm. A discrepancy between this value and the average size of In6Se7 nanocrystallites determined using the Williamson–Hall method (23.13 nm) has been discussed. With the help of the X-ray diffraction-absorption method, the average mass fraction of the In6Se7 phase in the investigated samples is determined, and the average concentration of In6Se7 nanocrystallites with an average size of about 26.5 nm over the volume of the layered α-In2Se3 matrix is calculated. A perspective character of the application of In2Se3/In6Se7 composite samples for operating in the optical telecommunication wavelength interval is discussed.