اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدStructure of Fe3Si/Al/Fe3Si thin film stacks on GaAs(001)
176
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Fe3Si/Al/Fe3Si/GaAs(001) structures were deposited by molecular-beam epitaxy and characterized by transmission and scanning electron microscopy, and x-ray diffraction. The first Fe3Si film on GaAs(001) is growing epitaxially as (001) oriented single crystal. The subsequent Al film grows almost 111 oriented in a fibre texture although the underlying Fe3Si is exactly (001) oriented. The growth in this orientation is triggered by a thin transition region which is formed at the Fe3Si/Al interface. In the end after the growth of the second Fe3Si layer on top of the Al the final properties of the whole stack depend on the substrate temperature T_S during deposition of the last film. The upper Fe3Si films are mainly 110 oriented although they are poly-crystalline. At lower T_S, around room temperature, all the films retain their original structural properties.
قيم البحث
اقرأ أيضاً
GaAs nanowires and GaAs-Fe3Si core-shell nanowire structures were grown by molecular-beam epitaxy on oxidized Si(111) substrates and characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Ga droplets were formed on the o
xide surface, and the semiconducting GaAs nanowires grew epitaxially via the vapor-liquid-solid mechanism as single-crystals from holes in the oxide film. We observed two stages of growth of the GaAs nanowires, first the regular growth and second the residual growth after the Ga supply was finished. The magnetic Fe3Si shells were deposited in an As-free chamber. They completely cover the GaAs cores although they consist of small grains. High-resolution TEM micrographs depict the differently oriented grains in the Fe3Si shells. Selected area diffraction of electrons and XRD gave further evidence that the shells are textured and not single crystals. Facetting of the shells was observed, which lead to thickness inhomogeneities of the shells.
GaAs nanowires and GaAs/Fe3Si core/shell nanowire structures were grown by molecular-beam epitaxy on oxidized Si(111) substrates and characterized by transmission electron microscopy. The surfaces of the original GaAs NWs are completely covered by ma
gnetic Fe3Si exhibiting nanofacets and an enhanced surface roughness compared to the bare GaAs NWs. Shell growth at a substrate temperature of T{S} = 200 {deg}C leads to regular nanofacetted Fe3Si shells. These facets, which lead to thickness inhomogeneities of the shells, consist mainly of well pronounced Fe3Si(111) planes. The crystallographic orientation of core and shell coincide, i.e. they are pseudomorphic. The nanofacetted Fe3Si shells found in the present work are probably the result of the Vollmer-Weber island growth mode of Fe3Si on the {110} side facets of the GaAs NWs.
Molecular beam epitaxy of Fe3Si on GaAs(001) is studied in situ by grazing incidence x-ray diffraction. Layer-by-layer growth of Fe3Si films is observed at a low growth rate and substrate temperatures near 200 degrees Celsius. A damping of x-ray inte
nsity oscillations due to a gradual surface roughening during growth is found. The corresponding sequence of coverages of the different terrace levels is obtained. The after-deposition surface recovery is very slow. Annealing at 310 degrees Celsius combined with the deposition of one monolayer of Fe3Si restores the surface to high perfection and minimal roughness. Our stoichiometric films possess long-range order and a high quality heteroepitaxial interface.
Thin film quasicrystal coatings have unique properties such as very high electrical and thermal resistivity and very low surface energy. A nano quasicrystalline thin film of icosahedral Al-Ga-Pd-Mn alloy, has produced by flash evaporation followed by
annealing. Attempts will be made to discuss the micromechanisms for the formation of quasicrystalline thin film in Al-Ga-Pd-Mn alloys
Mulheran and Blackman have provided a simple and clear explanation of the scale invariance of the island size distribution at the early stage of film growth [Phil. Mag. Lett. 72, 55 (1995)]. Their theory is centered on the concept of capture zone pro
perly identified by Voronoi cell. Here we substantiate experimentally their theory by studying the scale invariance of InAs quantum dots (QDs) forming on GaAs(001) substrate. In particular, we show that the volume distributions of QDs well overlap the corrisponding experimental distributions of the Voronoi-cell areas. The interplay between the experimental data and the numerical simulations allowed us to determine the spatial correlation length among QDs.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
