Texture and microstructure (domain size, dislocation density, concentration and effect of dopants incorporation, etc.) of thin films strongly influence on device operating characteristics. An increase of grain size and the improvement of grain crystalline quality lead to decrease of diffraction peak broadening when the evaluation of microstructure by common methods is impossible. In this case the dynamic scattering processes can take place and phenomenon of extinction can be observed. The characteristics of the primary and secondary extinction are related to the crystal microstructural feature and can be used for its evaluation [1]. It was shown in our previous work [2] that the phase transition temperature of ZnS:Cu thin films can be decreased by using of Cl as co-doping element and some annealing conditions. The explanation of the effect on the base of thin film microstructure was proposed.

We present the results of the structural investigations of ZnS:Cu thin films as-deposited and after a special annealing. The evaluation of thin film microstructure was performed by separation of the extinction phenomenon in pole density (PD) and determination of the coefficients of the primary and secondary extinction. To the best of our belief, the primary and secondary extinction simultaneously for microstructure determination of textured thin films have not been applied.

The ZnS:Cu thin films were deposited by electron beam evaporation method onto BaTiO₃ substrates with thickness of 0.8 – 1.6 μm. The annealing and doping with Cu, Cl and Ga were carried out at 800 - 950° C during one hour. The structural analysis was carried out by XDR techniques using D8 Bruker X-ray diffractometer with two non-polarized Cu and Co radiations. Low and high index reflections were measured. As-deposited ZnS:Cu films were strongly textured in <111> direction and had a cubic structure. After the annealing of ZnS:Cu films and doping with Cu, Cl and Ga a phase transition at lower temperature was observed. The values of PD in pole figures for the films measured for the first and second order reflections, showed the presence of extinction. The determined parameters of the extinction allowed to evaluate the domain thickness from the values of the primary extinction and the extinction length, and the average domain misorientation angle from the value of the secondary extinction and also the dislocation density N_D at domain boundaries. In the films with the strong phase transition the dislocation density decreased noticeably that leads to more homogeneous distribution of Cu and Cl in Zn and S sublattices and, hereby, increase the amount of Cu-Cl binding that affects the phase transition temperature.

1. Kryshtab T., Palacios-Gomez J., Mazin M. and Gomez-Gasga G., Acta Materialia, 2004, 52/10, 3027.

2. T. Kryshtab, V.S. Khomchenko, J.A. Andraca-Adame, V.B. Khachatryan, M.O. Mazin, V.E. Rodionov, M.F. Mukhlio, J. Crystal Growth 275, 2005, e1163.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/15351 must be provided.

1. Modification of the photoluminescence characteristics of CdZnTe/ZnTe QWs by CdTe monolayer film insertion