TITLE:
Unrelaxed State in Epitaxial Heterostructures Based on Lead Selenide
AUTHORS:
Arif Pashaev, Omari Davarashvili, Zaira Akhvlediani, Megi Enukashvili, Revaz Gulyaev, Vladimir Zlomanov
KEYWORDS:
Mismatch; Lattice Constant; Strained Layer; Unrelaxed State; Effective “Negative” Pressure; Optical Characterization
JOURNAL NAME:
Journal of Modern Physics,
Vol.3 No.6,
June
25,
2012
ABSTRACT: The work deals with the epitaxial PbSe layers grown on the KCl substrates by the method of “hot-wall” molecular epitaxy over the range of layer thicknesses of 20 - 2000 nm. Special emphasis is put on the values of elastic deformations that could be generated and frozen in epitaxial layers with the aim of influencing their energy spectra and optical properties. The maximum deformation at layers tension made up 57% of the initial mismatch between the layer and the substrate (ε = Δa/a = 0.015). In such a solid-state structure effective “negative” pressure is realized, which is justified by increase in the tangential lattice constant and the forbidden gap width. This width correlates with the tangential lattice constant (deformation) and corresponds to certain values of definite frequencies of direct electron transitions across the forbidden gap.