V. B. Ikonnikov

Effect of Hot Isostatic Pressing on the Elastic and Optical Properties of Polycrystalline CVD ZnS

Hot isostatic pressing (HIP) is shown to increase the Youngs modulus and transmittance of polycrystalline zinc sulfide produced by chemical vapor deposition. Both effects are associated with the decrease in the relative volume of nonequilibrium crystallite boundaries containing dangling bonds, which are responsible for the formation of bound surface charges, leading to interfacial polarization. The secondary recrystallization induced by HIP leads to the formation of thin, equilibrium grain boundaries.

Recrystallization Behavior of ZnS during Hot Isostatic Pressing

The effect of hot isostatic pressing conditions on the microstructure of CVD ZnS has been studied. The results have been used to analyze the mechanisms of zinc sulfide recrystallization at high temperatures and pressures.

Optical losses in polycrystalline CVD ZnS

We discuss the reasons for the limited visible and near-IR transmittance of polycrystalline zinc sulfide produced by chemical vapor deposition (CVD). Comparison of measured scattering indicatrices, depolarization ratios, and transmission spectra in the range 0.4–4 m with theoretical predictions leads us to conclude that a significant contribution to optical losses in CVD ZnS comes from light scattering by faceted submicron inclusions with a refractive index of 1 (pores). Assuming that these defects play a key role in determining the optical loss in the material, we have estimated the pore concentration and pore size distribution in CVD ZnS before and after hot isostatic pressing.

Recrystallization behavior of zinc chalcogenides during hot isostatic pressing

This paper examines the effect of hot isostatic pressing (HIP) on the recrystallization behavior of zinc chalcogenides prepared by chemical vapor deposition (CVD). We discuss the mechanisms of this process in CVD ZnS, ZnSe, and ZnSxSe1 − x at high temperatures and pressures and consider conditions under which secondary recrystallization occurs during HIP and high-temperature annealing.

Preparation of monolithic ZnSxSe1-x layers via chemical vapor deposition followed by hot isostatic pressing

A process is described for the preparation of monolithic ZnSxSe1−x (0.1 < x < 0.6) plates uniform in composition. The effect of hot isostatic pressing on the optical and structural properties of zinc sulfoselenide is examined.

Growth of structurally homogeneous CVD ZnSe plates

A model for the formation of the CVD ZnSe structure is proposed which takes into account the heat exchange between the surface of the growing crystal and the flow of gaseous reactants and the secondary recrystallization process at a varied substrate temperature. The calculation results are compared to experimental data. The time variation of the substrate temperature is optimized to achieve CVD of ZnSe with a homogeneous structure across the plate.

Temperature effect on the structure of ZnSe layers grown by chemical vapor deposition

The heat exchange between the substrate, growing layer, and gas flow in a CVD reactor is analyzed theoretically. The results indicate that the temperature of the gas mixture in the reactor influences the surface temperature of the polycrystalline zinc selenide deposit. Experimental data are presented on the variation of the average grain size across the ZnSe deposit. The thermal conditions of CVD and secondary crystallization during long-term deposition are shown to have a significant effect on the depth distribution of the grain size.

Distribution of luminescence centers in the bulk of undoped, Fe-doped, and Cr-doped CVD ZnSe polycrystals studied by two-photon confocal microscopy

Edge and defective-impurity luminescence in polycrystalline CVD ZnSe has been studied in the range 0.46–0.73 μm by two-photon confocal microscopy. We have obtained luminescence intensity distribution maps for undoped, iron-doped, and chromium-doped ZnSe samples at depths of up to 1 mm with a spatial resolution of a few microns. It has been shown that crystal regions with low dopant concentrations contain centers that luminesce in the ranges 520–580 and >670 nm. The parts of the crystals with high iron and chromium concentrations contain centers that suppress the edge and defective-impurity (520–580 nm) luminescence. We discuss the nature of these centers and demonstrate the possibility of assessing the luminescence characteristics of grain boundaries in CVD ZnSe.