There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Raman scattering and far-infrared absorption spectra of PbS nanocrystals with radii of 2 nm are presented. The experimental results are consistent with theoretical calculations which account correctly for the mechanical boundary conditions at the nanocrystal-host interface, and include the first observation of the mixed or coupled vibrational modes predicted by the theory.

/pdf/observation-of-coupled-vibrational-modes-of-a-semiconductor-51c2a2wxkw.pdf

Observation of coupled vibrational modes of a semiconductor nanocrystal

We report optical properties of PbTe and PbSe as obtained from first-principles calculations with the Tran-Blaha modified Becke-Johnson potential. The results are discussed in relation to existing experimental data, particularly in relation to the temperature dependence of the band gap.

Optical Properties of PbTe and PbSe

Key results of recent studies on cadmium sulfide nanoparticles are systematized. The dependence of the structure and properties of CdS nanoparticles on the nanoparticle size is illustrated. The possibility of utilizing CdS quantum dots as biological labels and sensitizers for solar cells is analyzed. The principles, features and potential of the method of aqueous solution deposition are described from the standpoint of synthesis of CdS nanocrystals and hybrid forms based on them with specified structure and properties.The bibliography includes 180 references.

https://iopscience.iop.org/article/10.1070/RCR4452/pdf

Cadmium sulfide nanoparticles prepared by chemical bath deposition

The mechanism of hydrolytic decomposition of thiocarbamide upon the interaction with metal salts with deposition of thin films of sulfide was proposed. The kinetic studies of the transformation of metal salt into sulfide and IR spectroscopy confirmed that one of the hydrolysis products of thiocarbamide was cyanamide. The concept about the activation of thiocarbamide decomposition was extended due to the nucleophilic addition of anions to form an intermediate reaction complex thiocarbamide—metal ion—nucleophile. The activation weakens in the order OH− > CH3COO− > Cl− > Br− > I−. The presence and active role of colloidal components of reaction mixtures in the nucleation and formation of films of metal sulfides by chemical bath synthesis were established by spectrophotometric and kinetic measurements. It was concluded that from the viewpoint of fractal formalism metal sulfide films are formed in chemical bath deposition via the mechanism of cluster—cluster aggregation in the form of consecutive evolution of structural levels. A complex scheme of the mechanism of chemical bath deposition of metal sulfides by thiocarbamide was proposed. The results of studies of their phase composition, microstructure, and properties are presented.

Nucleation and mechanism of metal sulfide film growth using deposition by thiocarbamide

Hydrochemical synthesis, structure, semiconductor properties of films of substitutional Pb1 − xSnxSe solid solutions

The effect of an ammonium iodide additive on the elemental and phase compositions, structural parameters, and surface morphology of lead selenide films synthesized by chemical deposition from aqueous solutions has been studied using X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray analysis. It has been established that the obtained PbSe films have a multiphase structure. The iodine content of the films is directly proportional to the NH4I concentration in the reaction mixture and increases linearly with an increase in this concentration to 0.25 mol/L. No individual iodine-containing phases have been detected in the film structure. However, the introduction of iodine leads to an increase in the PbSe phase lattice parameter from ∼6.11 to ∼6.16 A and to a decrease in the crystal grain size to ∼ 20 nm. It has been found that there is a correlation between the grain size, lattice parameter, and ammonium iodide concentration in the reaction mixture, which can be explained by changes in the film growth mechanism at the initial growth steps.

Effect of an iodine-containing additive on the composition, structure, and morphology of chemically deposited lead selenide films

Boundary conditions and ranges of the formation of indium(III) sulfide and selenide upon precipitation by thiocarbamide and selenocarbamide are determined. Potentiometric titration of indium chloride (InCl3) in the concentration range of 0.0001 to 0.100 mol/L by a solution of sodium hydroxide is performed. It is found that the following pH ranges are optimal for In2S3 and In2Se3 film precipitation: from 3.0 to 4.5 and from 9.0 to 14.0. Indium selenide layers 100 to 300 nm thick are prepared on vitroceramic by hydrochemcial precipitation.

/pdf/diagrams-of-the-formation-of-in-2-s-3-and-in-2-se-3-films-on-3hnnimikx2.pdf

Diagrams of the Formation of In 2 S 3 and In 2 Se 3 Films on Vitroceramic upon Precipitation, According to Potentiometric Titration

The growth mechanism of PbSeyS1 − y films has been studied upon chemical deposition from aqueous solutions using scanning probe microscopy. A comparative morphological analysis of layers deposited at the initial growth stages and the use of fractal formalism shows that the formation of films of PbS, PbSe, and PbSeyS1 − y substitutional solid solutions involves cluster-cluster aggregation with self-organization elements.

/pdf/mechanism-of-pbse-y-s-1-y-film-formation-in-chemical-3bb467qhg9.pdf

L. N. Maskaeva

Papers

Nucleation and mechanism of metal sulfide film growth using deposition by thiocarbamide

Hydrochemical synthesis, structure, semiconductor properties of films of substitutional Pb1 − xSnxSe solid solutions

Effect of an iodine-containing additive on the composition, structure, and morphology of chemically deposited lead selenide films

Diagrams of the Formation of In 2 S 3 and In 2 Se 3 Films on Vitroceramic upon Precipitation, According to Potentiometric Titration

Mechanism of PbSe y S 1 − y film formation in chemical deposition from aqueous solutions