The high-pressure behavior of amorphous selenium has been investigated with time-resolved diamond anvil cell synchrotron x-ray diffraction and computed microtomography techniques. A two-step dynamic crystallization process is observed in which the monoclinic phase crystallized from the amorphous selenium and gradually converted to the trigonal phase, thereby explaining previously observed anoma...

–We have investigated undoped hydrogenated amorphous silicon (a-Si:H) p-type crystalline silicon (c-Si) structures with and without a microcrystalline silicon (c-Si) buffer layer as a potential for hetero-junction (HJ) solar cell. Hydrogenated amorphous silicon and microcrystalline silicon film have been grown by inductively coupled plasma chemical vapour deposition (ICP-CVD). Solid phase crys...

Lithium-ion batteries using germanium as the anode material are attracting attention because of their high-capacity, higher conductivity, and lithium-ion diffusivity relative to silicon. Despite recent studies on Ge electrode reactions, there is still limited understanding of the reaction mechanisms governing crystalline Ge and the transformations into intermediate amorphous phases that form du...

Nanoscratching-induced deformation in monocrystaline silicon is found to depend on the loading conditions. Molecular dynamics simulations reveal that amorphous phase transformation and nanotwins are the two major mechanisms. At a relatively low scratching depth, amorphous transformation occurs on the surface; however, when the scratching depth is greater than 1 nm, nanotwinning also emerges in ...

In contrast with amorphous alloys, nanocrystalline soft magnetic materials show improved thermal stability and higher soft magnetic properties. The nanocrystalline soft magnetic composites are usually fabricated by partially crystallizing from parent amorphous alloys. This paper reports our experimental observation on the sequence of crystallization in metallic glass under a high magnetic field...

The thermally backward reaction involved in the mechanofluorochromism of dibenzoylmethanatoboron difluoride (BF2DBM) derivatives, accompanied by an amorphous-crystalline phase transition, was quantitatively evaluated based on kinetics and thermodynamics. The kinetics was discussed by evaluation of the effect of temperature on the time-dependent changes of the fluorescence intensity for amorphou...

We report on the pressure-induced phase transition in a model of paracrystalline silicon ~amorphous silicon with a crystalline grain! using an ab initio constant pressure simulation technique. The paracrystalline model transforms into a high-density amorphous phase at 16 GPa with a discontinuous volume change of ;24%. The transformation of the crystalline grain begins at the boundary and procee...

Time-dependent drift of resistance and threshold voltage in phase change memory (PCM) devices is of concern as it leads to data loss. Electrical drift in amorphous chalcogenides has been argued to be either due to electronic or stress relaxation mechanisms. Here we show that drift in amorphized Ge2Sb2Te5 nanowires with exposed surfaces is extremely low in comparison to thin-film devices. Howeve...

The detailed structure of a new dense amorphous ice, VHDA, is determined by isotope substitution neutron diffraction. Its structure is characterized by a doubled occupancy of the stabilizing interstitial location that was found in high density amorphous ice, HDA. As would be expected for a thermally activated unlocking of the stabilizing "interstitial," the transition from VHDA to LDA (low-dens...

Tight-binding molecular dynamics simulations shed light into the fracture mechanisms and the ideal strength of tetrahedral amorphous carbon and of nanocomposite carbon containing diamond crystallites, two of the hardest materials. It is found that fracture in the nanocomposites, under tensile or shear load, occurs intergrain and so their ideal strength is similar to the pure amorphous phase. Th...