Atomic ordering and bond relaxation in optical spectra of self-organized InP/GaInP2 Wigner molecule structures

A.M.M., D.V.L., and A.S.V. acknowledge the support of the Russian Science Foundation Grant No. 19-19-00246. K.G.B., M.V.R., and A.A.T. acknowledge the financial support of the Russian Foundation for Basic Research (Project No. 18-02-01212). This research was also enabled by the Science Foundation Ireland under Grant Nos. 15/IA/2864, 12/RC/2276, 12/RC/2276-P2, and 18/US/3512, and the Northern Ireland Department for the Economy (Grant No. USI-140). A.B.N. acknowledges support from EPSRC grant no. EP/R023751/1.We used transmission electron microscopy, Raman, and photoluminescence spectroscopy to identify the effect of CuPt-type GaP-InP atomic ordering (AO) on the structural and emission properties of self-organized (SO) InP/GaInP2 Wigner molecule (WM) quantum dot (QD) structures. We found that the correlation of AO and SO growth results in the formation of InP/GaInP2 QD/AO-domain (QD/AOD) core-shell composites. This observation shows that intrinsic WMs in this system emerge due to a strong piezoelectric field generated by AODs, which induces QD doping and a built-in magnetic field. We found that the bond relaxation of AODs leads to a decrease in the emission energy of WMs of 80 meV. The photoluminescence spectra of single WMs having an emission energy ∼1.53 eV are presented here, the lowest one reported for this system.Publisher PDFPeer reviewe

СИНТЕЗ И ХАРАКТЕРИЗАЦИЯ ТРИМЕТИЛ(ФЕНИЛ)СИЛАНА — ПРЕДШЕСТВЕННИКА ДЛЯ ГАЗОФАЗНЫХ ПРОЦЕССОВ ОСАЖДЕНИЯ ПЛЕНОК SiCx : H

The technique of synthesis and purification of trimethyl(phenyl)silane PhSiMe3, allowing to obtain the product with high yield. Individuality of the product was confirmed by elemental analysis for C, H, Si. IR, UV and 1H NMR–spectroscopic studies, defined its spectral characteristics. Complex thermal analysis and thermogravimetric defined thermoanalytical behavior effects of PhSiMe3 in an inert atmosphere. Tensimetric studies have shown that the compound has sufficient volatility and thermal stability for use as a precursor in the process of chemical vapor deposition (CVD). The composition and temperature limits of the possible crystalline phase complexes in equilibrium with the gas phase of different composition has been determed by method of thermodynamic modeling. Calculated CVD diagrams allow us to select the optimum conditions of film deposition. The possibility of using trimethyl(phenyl)silane in CVD processes for producing dielectric films of hydrogenated silicon carbide has been demonstrated. Разработана методика синтеза и очистки триметил(фенил)силана PhSiMe3, позволяющая получать целевой продукт с высоким выходом. Индивидуальность соединения подтверждена элементным анализом на C, H, Si. ИК−, УФ− и ЯМР−спектроскопическими исследованиями (1Н, 13C, 29Si) определены его спектральные характеристики. С помощью комплексного термического анализа определены термоаналитические и термогравиметрические эффекты поведения PhSiMe3 в инертной атмосфере. На основе данных тензометрических исследований показано, что это соединение обладает достаточной летучестью и термической устойчивостью для использования в качестве прекурсора в процессах химического осаждения из газовой фазы (CVD). Методом термодинамического моделирования определен состав и температурные границы возможных кристаллических фазовых комплексов в равновесии с газовой фазой различного состава. Рассчитанные CVD− диаграммы позволяют выбрать оптимальные условия процессов осаждения из газовой фазы пленок. Показана возможность использования PhSiMe3 в процессах CVD для получения диэлектрических пленок гидрогенизированного карбида кремния.

Blended Clustering for Health Data Mining

Exploratory data analysis using data mining techniques is becoming more popular for investigating subtle relationships in health data, for which direct data collection trials would not be possible. Health data mining involving clustering for large complex data sets in such cases is often limited by insufficient key indicative variables. When a conventional clustering technique is then applied, the results may be too imprecise, or may be inappropriately clustered according to expectations. This paper suggests an approach which can offer greater range of choice for generating potential clusters of interest, from which a better outcome might in turn be obtained by aggregating the results. An example use case based on health services utilization characterization according to socio-demographic background is discussed and the blended clustering approach being taken for it is described

Trimethyl(phenyl)silane — a precursor for gas phase processes of SiCx:H film deposition: Synthesis and characterization

The technique of synthesis and purification of trimethyl(phenyl)silane PhSiMe3, allowing to obtain the product with high yield. Individuality of the product was confirmed by elemental analysis for C, H, Si was developed. IR, UV and 1H NMR-spectroscopic studies were used to define its spectral characteristics. Complex thermal analysis and thermogravimetry defined thermoanalytical behavior of PhSiMe3 in an inert atmosphere. Tensimetric studies have shown that the compound has sufficient volatility and thermal stability for use as a precursor in the process of chemical vapor deposition (CVD). The composition and temperature limits of the possible crystalline phase complexes in equilibrium with the gas phase of different composition has been determined by method of thermodynamic modeling. Calculated CVD diagrams allow us to select the optimal conditions of film deposition. The possibility of using trimethyl(phenyl)silane in CVD processes for producing dielectric films of hydrogenated silicon carbide has been demonstrated