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Low Growth Temperature (low + growth_temperature)
Selected AbstractsGrowth behavior and microstructure of ZnO epilayer on ,-LiAlO2(100) substrate by chemical vapor depositionPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 2 2009Liuwen Chang Abstract Low lattice-mismatched ,-LiAlO2(100) substrates were employed to grow ZnO epitaxial films by chemical vapor deposition. The influence of growth temperature on growth behavior of ZnO was investigated. Results indicated that the low lattice-matched (100) crystallites nucleate on substrate at all growth temperatures employed. However, a second type of crystallites having an (0001) orientation can also nucleate on substrate at low growth temperature of 575 °C and 640 °C. The growth rate of the later crystallite is, however, higher than that of the (100) one and finally results in a single crystalline ZnO film having an [0001] azimuthal orientation. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] InGaAs channel MOSFET with self-aligned source/drain MBE regrowth technologyPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2009Uttam Singisetti Abstract InGaAs is a promising alternative channel material to Si for sub-22 nm node technology because of its low electron effective mass (m*) hence high electron velocities. We report a gate-first MOSFET process with self-aligned source/drain formation using non-selective MBE re-growth, suitable for realizing high performance scaled III-V MOSFETs. A W/Cr/SiO2 gate stack was defined on thin (4 nm/2.5 nm) InGaAs/InP channel by an alternating selective dry etch technique. A 5 nm Al2O3 layer was used as gate dielectric. An InAlAs bottom barrier provided vertical confinement of the channel. An in-situ H cleaning of the wafer leaves an epi-ready surface suitable for MBE or MOCVD regrowth. Source/Drain region were defined by non-selective MBE regrowth and in situ molybdenum contacts. First generation of devices fabricated using this process showed extremely low drive current of 2 ,A/,m. The drive current was limited by an extremely high source resistance. A regrowth gap between source/drain and gate was the cause for high source resistance. The gap in the regrowth was because of low growth temperature (400 °C). A modified high temperature growth technique resolved the problem. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Low threshold GaInAs quantum well lasers grown under low growth rate by solid-source MBE for 1200 nm wavelength rangePHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2006M. Ohta Abstract Optical property dependence on growth rates of highly-strained GaInAs quantum wells (QWs) on GaAs was studied by solid-source molecular beam epitaxy (MBE). Noticeable improvement of the photoluminescence (PL) was observed by lowering the growth rate of highly-strained GaInAs. A sample grown at a growth rate of 0.05 µm/h under a low growth temperature and high As pressure showed a high PL intensity and a flat surface in atomic force microscope (AFM) measurements. The lowest threshold current density of 117 A/cm2/well is achieved for GaInAs/GaAs double QW lasers at 1190 nm wavelength. A low growth rate is found to be effective to grow highly-strained GaInAs QWs. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Dynamic photo-inhibition and carbon gain in a C4 and a C3 grass native to high latitudesPLANT CELL & ENVIRONMENT, Issue 11 2004D. S. KUBIEN ABSTRACT C4 plants are rare in the cool climates characteristic of high latitudes and altitudes, perhaps because of an enhanced susceptibility to photo-inhibition at low temperatures relative to C3 species. In the present study we tested the hypothesis that low-temperature photo-inhibition is more detrimental to carbon gain in the C4 grass Muhlenbergia glomerata than the C3 species Calamogrostis Canadensis. These grasses occur together in boreal fens in northern Canada. Plants were grown under cool (14/10 °C day/night) and warm (26/22 °C) temperatures before measurement of the light responses of photosynthesis and chlorophyll fluorescence at different temperatures. Cool growth temperatures led to reduced rates of photosynthesis in M. glomerata at all measurement temperatures, but had a smaller effect on the C3 species. In both species the amount of xanthophyll cycle pigments increased when plants were grown at 14/10 °C, and in M. glomerata the xanthophyll epoxidation state was greatly reduced. The detrimental effect of low growth temperature on photosynthesis in M. glomerata was almost completely reversed by a 24-h exposure to the warm-temperature regime. These data indicate that reversible dynamic photo-inhibition is a strategy by which C4 species may tolerate cool climates and overcome the Rubisco limitation that is prevalent at low temperatures in C4 plants. [source] A che -like signal transduction cascade involved in controlling flagella biosynthesis in Rhodospirillum centenumMOLECULAR MICROBIOLOGY, Issue 5 2005James E. Berleman Summary Rhodospirillum centenum is a photosynthetic bacterium capable of undergoing swim cell to swarm cell differentiation that allows this species to be motile on both liquid and solid media. Previous experiments have demonstrated that the che1 operon is required for the control of chemotactic and phototactic behaviour of both swim and swarm cells. In this report, we analyse the function of a second che -like gene cluster in R. centenum, the che2 gene cluster. In-frame deletion mutants of cheW2, cheB2, cheR2, cheY2, and of the entire che2 operon, exhibit defects in swim and swarm cell motility. Analysis of these strains demonstrates that they are non-motile, and that the non-motile phenotype is resulting from reduced polar and lateral flagella synthesis. Additionally, mutations in mcp2, ORF204, cheA2 and ORF74 remain chemotacticly and phototacticly competent at both high and low growth temperatures. Mutations in these che2 genes result in elevated levels of flagellin proteins giving rise to a hyperflagellate phenotype. We propose a model in which R. centenum utilizes a che -like signal transduction pathway (che2) for regulating flagellum synthesis in order to optimize swim cell-swarm cell differentiation in response to changing environmental conditions. [source] Kinetic and strain-driven growth phenomena on Si(001)PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 2 2004C. Schelling Abstract Self-organization phenomena in semiconductors are usually based on strain-driven island growth during hetero epitaxial layer deposition. However, kinetic phenomena can become important and even dominating at the low growth temperatures usually employed during molecular beam epitaxy. We report on kinetic step bunching on Si(001), and identify the driving mechanism on the atomic scale via kinetic Monte Carlo simulations. Another phenomena discussed is facet formation during annealing of SiO2 -covered Si(001) nanostructures at the relatively low temperatures usually employed for oxide desorption. Both phenomena are combined to facilitate perfect ordering of self-assembled Ge dots on facetted Si(001) nanostructure templates. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||