Вплив механічної обробки поверхні на діелектричні та фотодіелектричні властивості кристалів AIIBVI

Abstract

The subject matter of the study is the dielectric and photodielectric properties of AIIBVI crystals of composition ZnSe and Cd1-хZnхTe, which are grown from the melt, and the structural defects and internal elastic fields associated with these properties. The goal of the article is to study the patterns of influence of surface machining by grinding, polishing, and local loading on the defective structure in the deformation region, and thus on the dielectric and photodielectric properties of AIIBVI crystals of this composition, which is important given the use of these crystals in aerospace engineering. The tasks to be solved are: to investigate the regularities of the influence of grinding, polishing, and local deformation of the chipped surface of ZnSe and Cd1-хZnхTe samples on their defective structure, dielectric and photodielectric properties, including irreversible changes in properties. The problems were solved by the following methods: dielectric and photodielectric properties of crystals were investigated by the capacitive method; scanning photodielectric spectroscopy was used to measure the photoionization energies of localized states of charge carriers in crystals; the distribution of residual elastic stresses in the samples was studied by the polarization-optical method. The following results were obtained. Grinding and polishing cause the transformation of own and impurity maxima of the spectral dependences of the dielectric parameters of AIIBVI crystals, has a characteristic effect on the coordinate dependences of the dielectric parameters of crystals Cd1-хZnхTe. This is due to the transformation of localized states of carriers, which is confirmed by the study of ZnSe crystals. Concentrated deformation of Cd1-хZnхTe crystals significantly affects their dielectric properties, in particular, causes relaxation of dielectric parameters. Conclusions. Mechanical surface treatment of AIIBVI crystals by grinding and polishing, as well as local mechanical loading of Cd1-хZnхTe samples significantly affect their dielectric and photodielectric properties, which is associated with the formation of a system of defects and internal elastic fields in the deformation regions. An explanation of the observed effects is given.