Electron microscopy study on the influence of B-implantation on Ni induced lateral crystallization in amorphous Si

Nickel Metal Induced Lateral Crystallization (Ni-MILC) emerged as a viable technique for crystallization of a-Si films decreasing the crystallization temperature. Boron (B) implantation on a-Si films significantly enhances the crystallization rate of the Ni-MILC process. The structural characteristics of the implanted by Boron and subsequently crystallized by MILC a-Si films are studied by Transmission Electron Microscopy (TEM) and they are compared to intrinsic a-Si films which were deposited on top, as well as beside the boron implanted a-Si film. During the annealing, spontaneous nucleation occurs in the B-doped films far from the a-c interface, revealing a shorter incubation period in the B-doped films

Unraveling the sequence of serpentinization reactions : petrography, mineral chemistry, and petrophysics of serpentinites from MAR 15°N (ODP Leg 209, Site 1274)

Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 33 (2006): L13306, doi:10.1029/2006GL025681.The results of detailed textural, mineral chemical, and petrophysical studies shed new light on the poorly constrained fluid-rock reaction pathways during retrograde serpentinization at mid-ocean ridges. Uniformly depleted harzburgites and dunites from the Mid-Atlantic Ridge at 15°N show variable extents of static serpentinization. They reveal a simple sequence of reactions: serpentinization of olivine and development of a typical mesh texture with serpentine-brucite mesh rims, followed by replacement of olivine mesh centers by serpentine and brucite. The serpentine mesh rims on relic olivine are devoid of magnetite. Conversely, domains in the rock that are completely serpentinized show abundant magnetite. We propose that low-fluid-flux serpentinization of olivine to serpentine and ferroan brucite is followed by later stages of serpentinization under more open-system conditions and formation of magnetite by the breakdown of ferroan brucite. Modeling of this sequence of reactions can account for covariations in magnetic susceptibility and grain density of the rocks.Funding for this research was provided by USSSP and NSF-OCE grant 9986135. WB acknowledges support through a fellowship by the Deep Ocean Exploration Institute