RESUMO
Mg-Zn co-dopedGaN powders via the nitridation of a Ga-Mg-Zn metallic solution at 1000 °C for 2 h in ammonia flow were obtained. XRD patterns for the Mg-Zn co-dopedGaN powders showed a crystal size average of 46.88 nm. Scanning electron microscopy micrographs had an irregular shape, with a ribbon-like structure and a length of 8.63 µm. Energy-dispersive spectroscopy showed the incorporation of Zn (Lα 1.012 eV) and Mg (Kα 1.253 eV), while XPS measurements showed the elemental contributions of magnesium and zinc as co-dopant elements quantified in 49.31 eV and 1019.49 eV, respectively. The photoluminescence spectrum showed a fundamental emission located at 3.40 eV(364.70 nm), which was related to band-to-band transition, besides a second emission found in a range from 2.80 eV to 2.90 eV (442.85-427.58 nm), which was related to a characteristic of Mg-doped GaN and Zn-doped GaN powders. Furthermore, Raman scattering demonstrated a shoulder at 648.05 cm-1, which could indicate the incorporation of the Mg and Zn co-dopants atoms into the GaN structure. It is expected that one of the main applications of Mg-Zn co-doped GaN powders is in obtaining thin films for SARS-CoV-2 biosensors.
RESUMO
This work presents the theoretical calculation of isotherm diagrams for quaternary alloys of III-V semiconductor compounds with the form IIIxIII1-xVyV1-y. In particular, the isotherm diagrams for the AlxGa1-xAsySb1-y quaternary alloy at low temperatures were calculated (500 °C, 450 °C, 400 °C, and 350 °C). The AlxGa1-xAsySb1-y quaternary alloy was formed from four binary compounds such as GaAs, AlAs, AlSb, and GaSb, all with direct bandgaps. The regular solution approximation was used to find the quaternary isotherm diagrams, represented in four linearly independent equations, which were solved using Parametric Technology Corporation Mathcad 14.0 software for different arsenic and antimony atomic fractions. The results support the possible growth of layers via liquid-phase epitaxy in a range of temperatures from 500 °C to 350 °C, where the crystalline quality could be improved at low temperatures. These semiconductor layers could have applications for optoelectronic devices in photonic communications, thermophotovoltaic systems, and microwave devices with good crystalline quality.
RESUMO
El objetivo del trabajo fue determinar si existe relación significativa entre el nivel de calidad de vida y la condición de dependencia del adulto mayor que reside en la ciudad de Chimbote, en el año 2012. El estudio incluyó un tamaño de muestra mínimo de 171 adultos mayores, pero debido a disponibilidad de información se trabajó con 181, donde evaluamos la condición de dependencia y el nivel de calidad de vida, del adulto mayor, así como la relación entre ambas. Los resultados fueron que el 22,1% de adultos mayores tienen calidad de vida muy alta, el 20,4% tienen calidad de vida muy baja, y el 19,9% están en el nivel normal. De otro lado más de la mitad de adultos mayores son independientes en las actividades de la vida diaria, es decir el 56,45% son independientes y un 2,2% tienen dependencia grave. Además se encontró que existe relación altamente significativa entre condición de dependencia y calidad de vida del adulto mayor que reside en la ciudad de Chimbote en el año 2012.
The objective was to determine if there is significant relationship between the level of quality of life and dependency status of older adults living in the city of chimbote, in 2012. The study included a minimum sample size of 171 older adults, but due to availability of information is worked with 181, where we evaluate dependency status and quality of life, the elderly, and the relationship between them. The results were that 22.1% of older adults have very high quality of life, 20.4% had very low quality of life, and 19.9% are in the normal range. On the other hand more than half of older adults are independent in activities of daily living ie 56.45% are independent and 2.2% have severe dependence. It was also found that there is a highly significant relationship between dependency status and quality of life of older aduults living in the city of Chimbote in 2012.
