Gas-phase synthesis of single crystals of Ge–Si system

In this study, the synthesis of single crystals of solid solutions Ge[Formula: see text]Si[Formula: see text] from the gas phase was performed in two different variants. Here, the vapor phase is created in a closed volume. A special ampoule has been made for this purpose. Ge–Si is placed near one end of the ampoule. A temperature gradient is created along the ampoule. The temperature of the hot zone was chosen to be [Formula: see text]C and the temperature of the cold zone to be [Formula: see text]C. It has been found that single crystals can form not only on the polycrystalline layer, but also from separate centers on the walls of the ampoule.

Epitaxial K 0.5 Na 0.5 NbO 3 thin films by aqueous chemical solution deposition

We report on an environmentally friendly and versatile aqueous chemical solution deposition route to epitaxial K 0.5 Na 0.5 NbO 3 (KNN) thin films. The route is based on the spin coating of an aqueous solution of soluble precursors on SrTiO 3 single crystal substrates followed by pyrolysis at 400°C and annealing at 800°C using rapid thermal processing. Strongly textured films with homogeneous thickness were obtained on three different crystallographic orientations of SrTiO 3 . Epitaxial films were obtained on (111) SrTiO 3 substrates, while films consisting of an epitaxial layer close to the substrate followed by an oriented polycrystalline layer were obtained on (100) and (110) SrTiO 3 substrates. A K 2 Nb 4 O 11 secondary phase was observed on the surface of the thin films due to the evaporation of alkali species, while the use of an NaCl/KCl flux reduced the amount of the secondary phase. Ferroelectric behaviour of the films was investigated by PFM, and almost no dependence on the film crystallographic orientation was observed. The permittivity and loss tangent of the films with the NaCl/KCl flux were 870 and 0.04 (100-orientation) and 2250 and 0.025 (110-orientation), respectively, at 1 kHz.

Silk/molecular conductor bilayer thin-films: properties and sensing functions

A polycrystalline layer of (BEDT-TTF)2I3-based molecular conductor is transferred from a polycarbonate template to silk and other substrates for sensing and actuation applications.

Evidence for correlated structural and electrical changes in a Ge2Sb2Te5thin film from combined synchrotron X-ray techniques and sheet resistance measurements duringin situthermal annealing

The temperature-induced phase transition in an as-deposited amorphous Ge2Sb2Te5(GST) thin film was studied by a unique combination ofin situsynchrotron techniques (diffraction and reflectivity of X-rays) and sheet resistance measurements. The combination of these characterization techniques allowed the simultaneous extraction of structural (density and film thickness) and electrical characteristics of the GST film during its thermal annealing. It is shown that, at 425 (3) K, the appearance of diffraction peaks associated with a metastable crystalline cubic phase is unambiguously correlated to a density increase in combination with a layer thickness reduction and a resistivity switch towards a lower-resistance state. Under the present annealing conditions, the Ge2Sb2Te5film consists of a polycrystalline layer capped by an amorphous layer that strongly degrades the electrical conductivity.

Study on Subsurface Damage Model of the Ground Monocrystallinge Silicon Wafers

In order to better understand the grinding mechanism, the rough, semi-fine and fine ground silicon wafer subsurface damage models are experimentally investigated with the aid of advanced measurement methods. The results show that the rough ground wafer subsurface damage model is composed of large quantity of microcracks with complicated configurations, high density dislocations, stalk faults and elastic deformation layer. Among them microcracks, dislocations and stalk faults are dominant. Apart from the above damage, the amorphous layer and polycrystalline layer (Si-I, Si-III, Si-IV and Si-XII) exist in the semi-fine ground and fine ground wafer subsurface damage models. The amorphous layer depth firstly increases from rough grinding to semi-fine grinding and then decreases from semi-fine grinding to fine grinding. The damage model can be divided in severe damage part and elastic deformation part with high stress. When the material is removed by ductile mode two parts are all small and the ratio of second part is relatively great.

Formation of Aluminium Nitride during Sintering of Powder Injection Moulded Aluminium

A TEM study of aluminium nitride formed during sintering of powder injection moulded aluminium under nitrogen is presented. A polycrystalline layer consisting of fine, rod-shaped crystallites of hexagonal AlN formed on the Al powder surfaces. The grain boundaries exhibit a double layer of AlN separated by a thin layer of Al. The structure of the AlN is characterised and its influence upon sintering discussed.

A superlattice approach to the synthesis of ferroelectric Strontium Bismuth Tantalate thin films using liquid-injection-MOCVD

The synthesis of SrBi2Ta2O9 (SBT) thin films has been investigated using a superlattice approach. Thin films were deposited on silicon by independent injection of each source to produce Bi2O3/SrTa2O6 superlattices. The effects of post-deposition annealing have been investigated using high-resolution TEM and medium energy ion scattering (MEIS) to depth profile the superlattices. X-ray diffraction has also been used to characterize the conversion of the superlattices from distinct layers of Bi2O3 and SrTa2O6 into a polycrystalline layer of strontium bismuth tantalate.