Formation of Palladium Silicide on Heavily Doped Si(001) Substrates Using Ti Intermediate Layer

The formation of palladium silicide on Pd/Ti/Si systems with and without heavy B-doping has been investigated. For comparison, Pd2Si was also formed on Pd/Si systems. The agglomeration of Pd2Si could be retarded in Pd/Ti/Si systems with and without B-doping after annealing at 600 � C. The existence of the Ti layer could improve the thermal stability of Pd2Si. In addition, epitaxial or highly oriented Pd2Si formed in Pd/Ti/Si systems. The two orientation relationships of Pd2Si layers were identified to be Pd2Si½1� 1 10�k Si½ � 1 110� and Pd2Si½110�k Si½001�, and Pd2Si½100�k Si½ � 1 110� and Pd2Si½001�k Si½001�. The formation of strained epitaxial Pd2Si layers was found in Pd/Ti/Si systems. The improvement in the thermal stability of Pd2Si and the formation of epitaxial or highly oriented Pd2Si in Pd/Ti/Si systems were observed with and without B- doping

Formation of Palladium Silicide Thin Layers on Si(110) Substrates

The formation of palladium silicide thin films from Pd/Si(110) and Pd/Si(001) systems with and without a Ti intermediate layer has been investigated. The existence of a Ti layer could improve the thermal stability of Pd2Si thin layers in Pd/Ti/Si(001). In addition, an epitaxial or highly oriented Pd2Si layer is formed in Pd/Ti/Si systems. However, the roughness of the Pd2Si/Si interface is observed in Pd/Ti/Si(110) systems, while the flatnesses of the Pd2Si/Si interface is observed in Pd/Ti/Si(001)

Uteluftsventilerad krypgrund, teori och praktik

Uteluftsventilerade krypgrunder är kända för att kunna drabbas av problem med hög relativ luftfuktighet inne i kryputrymmet. Förhållandena som uppstår kan då vara gynnsamma för biologisk påväxt vilket i sin tur kan ha en negativ inverkan på både konstruktionens hållfasthet och inomhusluftens kvalitet. Problem uppstår dels på grund av att krypgrunden förblir för kall sommartid och dels på grund av en hög fuktbelastning från underliggande mark. I denna rapport härleds nya teoretiska samband för att beskriva hur temperaturen vid blindbotten inne i krypgrunden beror av temperaturen inomhus, utomhus och vid grundbotten. Metoden kan användas för att uppskatta hur relativa luftfuktigheten varierar inne i kryputrymmet och hur denna påverkas av olika åtgärder. Forskningsarbetet har här riktat in sig på att undersöka effekten av ventilation kombinerat med värmetillförsel, och en framtagen regleralgoritm påvisar att värmetillförsel kan användas periodvis under kritiska perioder för att öka mängden fukt som ventilation kan föra ut ur krypgrunden.Outdoor air-ventilated crawls spaces are known to face problems caused by a high relative humidity inside the crawl space. The conditions then become favourable for different types of biological fouling. This in turn can have a negative impact on both the structural properties of building materials and the quality of the indoor air. Problems with high relative humidity are partly due to insufficient heating of the crawl space during the summer and partly due to a high moisture load from the ground below. In this report, new theoretical relations are derived that explain how the temperature beneath the floor structure is related to the temperature indoors, outdoors, and at the ground surface. The method can be used to estimate how the relative humidity varies inside the crawl space and how it can be affected by different measures. We have focused on measures based on combinations of controlled ventilation and heating, and developed a control algorithm which suggests that additional heating could be used periodically, during critical periods, to increase the amount of moisture that can be removed from the crawl space using ventilation

Invited; Epitaxy and heterostructure of germanium tin-related group-IV alloy semiconductors for future electronic and optoelectronic applications

GeSn and related group-IV alloys have been much attracted as one of novel semiconductor materials for nextgeneration nanoelectronics, optoelectronics, and thermoelectronics applications. GeSn semiconductor promises high carrier mobility, highly efficient optoelectronic conversion, low thermal conductivity, and also low thermal budget process those properties are appropriate for the integration on Si ULSI platform. On the other hand, there are some challenges for practical applications of GeSn thin films integrating into Si ULSI. One is realizing a high substitutional Sn content over several percents in GeSn and related alloys, since the thermal equilibrium solid-solubility of Sn in Ge is as low as 1% (0.1% in the case of Si). In addition, the strain control of GeSn heteroepitaxial layers with a high crystalline quality is required for energy band engineering. Thus, it is necessary to understand and establish the crystal growth science and technology of GeSn-related group-IV thin films to control those crystalline and electronic properties. Please click Download on the upper right corner to see the full abstract

Growth and applications of GeSn-related group-IV semiconductor materials

We review the technology of Ge1−xSnx-related group-IV semiconductor materials for developing Si-based nanoelectronics. Ge1−xSnx-related materials provide novel engineering of the crystal growth, strain structure, and energy band alignment for realising various applications not only in electronics, but also in optoelectronics. We introduce our recent achievements in the crystal growth of Ge1−xSnx-related material thin films and the studies of the electronic properties of thin films, metals/Ge1−xSnx, and insulators/Ge1−xSnx interfaces. We also review recent studies related to the crystal growth, energy band engineering, and device applications of Ge1−xSnx-related materials, as well as the reported performances of electronic devices using Ge1−xSnx related materials

A compound-specific n-alkane δ13C and δD approach for assessing source and delivery processes of terrestrial organic matter within a forested watershed in northern Japan

We measured molecular distributions and compound-specific hydrogen (δD) and stable carbon isotopic ratios (δ13C) of mid- and long-chain n-alkanes in forest soils, wetland peats and lake sediments within the Dorokawa watershed, Hokkaido, Japan, to better understand sources and processes associate with delivery of terrestrial organic matter into the lake sediments. δ13C values of odd carbon numbered C23-C33 n-alkanes ranged from -37.2 to -31.5 ‰, while δD values of these alkanes showed a large degree of variability that ranged from -244 to -180 ‰. Molecular distributions in combination with stable carbon isotopic compositions indicate a large contribution of C3 trees as the main source of n-alkanes in forested soils whereas n-alkanes in wetland soil are exclusively derived from marsh grass and/or moss. We found that the n-alkane δD values are much higher in forest soils than wetland peat. The higher δD values in forest samples could be explained by the enrichment of deuterium in leaf and soil waters due to increased evapotranspiration in the forest or differences in physiology of source plants between wetland and forest. A δ13C v.s. δD diagram of n-alkanes among forest, wetland and lake samples showed that C25-C31 n-alkanes deposited in lake sediments are mainly derived from tree leaves due to the preferential transport of the forest soil organic matter over the wetland or an increased contribution of atmospheric input of tree leaf wax in the offshore sites. This study demonstrates that compound-specific δD analysis provides a useful approach for better understanding source and transport of terrestrial biomarkers in a C3 plant-dominated catchment

Impedance spectroscopy of GeSn/Ge heterostructures by a numerical method

peer reviewedIn this work, we investigated the electrical characteristics of p-GeSn/p-Ge and p-GeSn/n-Ge structures obtained by simulation of the semiconductor equations. We developed a numerical formalism based on a drift-diffusion model including a trap level and applied it to typical GeSn-based heterostructures by focusing on the electrical response under small-signal alternating current regime. The results demonstrate that our method provides an access to both microscopic and macroscopic properties, and thereon, to a physical interpretation of the electrical characteristics of GeSn-based structures by linking measurable quantities to micro-scale variations in the structures

Fluxes, source and transport of organic matter in the western Sea of Okhotsk: Stable carbon isotopic ratios of n-alkanes and total organic carbon

Settling particles and surface sediments collected from the western region of the Sea of Okhotsk were analyzed for total organic carbon (TOC), long-chain n-alkanes and their stable carbon isotope ratio (δ13C) to investigate sources and transport of total and terrestrial organic matter in the western region of the sea. The δ13C measurements of TOC in time-series sediment traps indicate lateral transport of resuspended organic matter from the northwestern continental shelf to the area off Sakhalin via the dense shelf water (DSW) flow at intermediate depth. The n-alkanes in the surface sediments showed strong odd carbon number predominance with relatively lighter δ13C values (from −33‰ to −30‰). They fall within the typical values of C3-angiosperms, which is the main vegetation in east Russia, including the Amur River basin. On the other hand, the molecular distributions and δ13C values of n-alkanes in the settling particles clearly showed two different sources: terrestrial plant and petroleum in the Sea of Okhotsk. We reconstructed seasonal change in the fluxes of terrestrial n-alkanes in settling particles using the mixing model proposed by Lichtfouse and Eglinton [1995. 13C and 14C evidence of a soil by fossil fuel and reconstruction of the composition of the pollutant. Organic Geochemistry 23, 969–973]. Results of the terrestrial n-alkane fluxes indicate that there are two transport pathways of terrestrial plant n-alkanes to sediments off Sakhalin, the Sea of Okhotsk. One is lateral transport of resuspended particles with lithogenic material from the northwestern continental shelf by the DSW flow. Another is the vertical transport of terrestrial plant n-alkanes, which is independent of transport of lithogenic material. The latter may include dry/wet deposition of aerosol particles derived from terrestrial higher plants possibly associated with forest fires in Siberia