Characteristics of interface corrugations in short-period GaAs/AlAs superlattices

GaAs/AlAs supelattices with corrugated interfaces have been investigated by the polarized photoluminescence method. Using the theoretical approach, which associates the linear polarization of exciton photoluminescence with the corrugation parameters, experimental results have been fitted to determine the height and lateral extension of corrugations.Методом поляризованої фотолюмінесценції досліджені надгратки GaAs/AlAs з коругованими гетеромережами. Співставляючи експериментальні результати з теоретичними розрахунками на основі моделі, яка пов'язує ступінь лінійної поляризації екситонної фотолюмінесценції з параметрами коругованостей, визначені висота та латеральна протяжність коругованостей.Методом поляризованной фотолюминесценции исследованы сверхрешетки GaAs/AlAs с корругированными гетерограницами. Путем сравнения експериментальных результатов с теоретическими расчетами, базирующимися на модели, которая связывает степень линейной поляризации экситонной фотолюминесценции з параметрами корругованностей, определены высота и латеральная протяженность корругованностей

Characterization of ultrashort-period GaAsrAlAs superlattices by exciton photoluminescence

Abstract Ultrashort-period GaAsrAlAs superlattices of type-II were investigated by low-temperature photoluminescence spectroscopy. The photoluminescence spectra consisting of many lines were carefully analyzed to obtain energy position, full width at half maximum and relative intensity for each individual line. Influence of the energy band structure, layer thickness and interface disorder on the radiative electron-hole transitions in these structures is discussed.

Electronic properties of surface vacancies in CdS nanocrystals

Structural and electronic characteristics of neutral and charged vacancies of cadmium and sulfur in CdS nanocrystals have been performed using the density functional method with hybrid exchange-correlation functional. Total and partial density of states, formation energies and the energies of thermodynamic transitions were calculated. Based on these theoretical findings and available experimental data, we can confirm the assumption, that the singly charged vacancies of cadmium are the centers of radiative recombination in such the structures. Key words: Cadmium sulfide, nanocrystal,  photoluminescence, vacancy, density functional method.</p

Photoluminescent Properties of CdTe Nanocrystals in Colloidal Solutions and Polymer Films

Using stabilizers and promoters we have obtained colloidal CdTe nanocrystals (NCs) in aqueous solutions. Incorporation of the CdTe NCs into polymer films has been fulfilled subsequently. It is shown that the use of vinyl acetate-acrylate copolymer as the matrix material for CdTe NC incorporation from colloidal solutions allows to get stable and nontoxic nanoheterogeneous film structures, which are characterized by satisfactory values of the photoluminescence quantum yield. Photoluminescence characteristics of the studied materials have been analyzed. Keywords: cadmium telluride, nanocrystal, vinyl acetate-acrylate copolymer, photoluminescence spectra, photoluminescence quantum yield.</p

Features of manufacturing Cd1–xZnxTe ionizing radiation detector

The article describes a newly-developed method of manufacturing of an operating element of the Cd1–xZnxTe-detector of ionizing radiation with high sensitivity to low-energy gamma radiation of the americium 241Am radioactive isotope. The proposed two-step method of chemical surface treatment with the use of new bromine releasing polishing etchants significantly improves the quality of the detector material and increases its specific sensitivity to ionizing radiation. This allows to use smaller Cd1–xZnxTe plates, which results in lowering of the cost of detectors