An amorphous mixing layer (3.5–4.0 nm in thickness) containing silicon (Si), oxygen (O), molybdenum (Mo) atoms, named <i>α</i>-SiO_<i>x</i>(Mo), is usually formed by evaporating molybdenum trioxide (MoO₃) powder on an n-type Si substrate. In order to investigate the process of adsorption, diffusion and nucleation of MoO₃ in the evaporation process and ascertain the formation mechanism of <i>α</i>-SiO_<i>x</i>(Mo) on a atomic scale, the first principle calculation is used and all the results are obtained by using the Vienna <i>ab initio</i> simulation package. The possible adsorption model of MoO₃ on the Si (100) and the defect formation energy for substitutional defects and vacancy defects in <i>α</i>-SiO₂ and <i>α</i>-MoO₃ are calculated by the density functional theory. The results show that an amorphous layer is formed between MoO₃ film and Si (100) substrate according to <i>ab initio</i> molecular dynamics at 1500 K, which are in good agreement with experimental observations. The O and Mo atoms diffuse into Si substrate and form the bonds of Si—O or Si—O—Mo, and finally, form an <i>α</i>-SiO_<i>x</i>(Mo) layer. The adsorption site of MoO₃ on the reconstructed Si (100) surface, where the two oxygen atoms of MoO₃ bond with two silicon atoms of Si (100) surface, is the most stable and the adsorption energy is －5.36 eV, accompanied by the electrons transport from Si to O. After the adsorption of MoO₃ on the Si substrate, the structure of MoO₃ is changed. Two Mo—O bond lengths of MoO₃ are 1.95 Å and 1.94 Å, respectively, elongated by 0.22 Å and 0.21 Å compared with the those before the adsorption of MoO₃ on Si substrate, while the last bond length of MoO₃ is little changed. The defect formation energy value of neutral oxygen vacancy in <i>α</i>-SiO₂ is 5.11 eV and the defect formation energy values of neutral oxygen vacancy in <i>α</i>-MoO₃ are 0.96 eV, 1.96 eV and 3.19 eV, respectively. So it is easier to form oxygen vacancy in MoO₃ than in SiO₂, which implies that the oxygen atoms will migrate from MoO₃ to SiO₂ and forms a 3.5–4.0-nm-thick <i>α</i>-SiO_<i>x</i>(Mo) layer. As for the substitutional defects in MoO₃ and SiO₂, Mo substitutional defects are most likely to form in SiO₂ in a large range of Mo chemical potential. So based on our obtained results, the forming process of the amorphous mixing layer may be as follows: the O atoms from MoO₃ bond with Si atoms first and form the SiO_<i>x</i>. Then, part of Mo atoms are likely to replace Si atoms in SiO_<i>x</i>. Finally, the ultra-thin buffer layer containing Si, O, Mo atoms is formed at the interface of MoO₃/Si. This work simulates the reaction of MoO₃/Si interface and makes clear the interfacial geometry. It is good for us to further understand the process of adsorption and diffusion of atoms during evaporating, and it also provides a theoretical explanation for the experimental phenomenon and conduces to obtaining better interface passivation and high conversion efficiency of solar cell.

Diffusion of implanted Mo in the Zr57Nb5Cu15.4Ni12.6Al10 bulk non-crystalline alloy has been researched using secondary ion mass spectroscopy (SIMS). Activation energy Q and pre-exponential factor D0 were obtained to be 1.95 eV and 1.13×10-5m2s-1, respectively. Based on the Stokes-Einstern relation, the viscosity of the Zr57Nb5Cu15.4Ni12.6Al10 bulk non-crystalline alloy was investigated at temperatures below the glass transition, it decreases with the increase of temperature from 1.07×1010 Poise at 593 K to 1.42×108 Poise at 673 K.

Molecular dynamics (MD) simulation and first-principles calculation were used to study the heredity characteristics, evolution trend and structural stability of basic clusters during the rapid solidification of Pd₈₂Si₁₈ alloy. The local atomic structures were characterized by the pair distribution function g(r) and the extended cluster-type index method (CTIM). The MD simulations reveal that the number of bi-cap Archimedes anti-prism (BSAP) clusters with CTIM index (10 2/1441 8/1551) is dominant in the amorphous solids rather than three-cap triangular prism(TTP) with CTIM index (9 3/1441 6/1551), which is identified be the most popular basic units in Pd₈₂Si₁₈ alloys analyzed by Voronoi index Relative to other basic clusters, the Si-centered BSAP possesses much larger fraction in the glassy state of Pd₈₂Si₁₈ alloys. Different from the findings in Cu-Zr alloys, the Si-centered BSAP instead of icosahedra has a larger hereditary fraction than any other Kasper clusters. During the solidification, it was found that most of the other Si-centered basic clusters are transferred into BSAP. Via the DFT calculations, it is observed that the Si-centered basic clusters with higher fraction of heredity and possesses lower binding energy. Among of them, BSAP always keeps lower binding energy than any other Si-centered Kasper clusters during the rapid solidification, resulting in its highest structural stability and the largest heredity fraction.