Heterogeneous growth of single crystals on polycrystals

Abstract

This work discloses a surprising, previously unknown heterogeneous growth mode. Namely, large-area, thin sheets of single-crystalline Ge were observed to grow laterally on top of a polycrystalline Al substrate, covering as many as tens of differently oriented Al grains at low temperatures. The observation of the Ge crystal-growth process by in situ heating transmission electron microscopy demonstrates an intriguing type of "faceted" growth: the growth of single-crystalline Ge thin sheets proceeding Al-grain by Al-grain on top of the polycrystalline Al substrate. The crystalline Ge growth front tends to align along the lines of intersection of the Al grain boundaries with the Al surface. Such an unusual heterogeneous growth mode has been shown to be a consequence of the strong anisotropy of the energy of the crystalline/crystalline (here: c-Ge/c-Al) interfaces.

Effect of Sn on crystallinity and electronic property of low temperature grown polycrystalline-Si1−−Ge Sn layers on SiO2

“…Previous works have been reported in which the crystallization temperature of amorphous-Si (a-Si) and a-Si 1Àx Ge x to polycrystal phase can be reduced by metal introduce crystallization (MIC) process using Ni and Al [5][6][7][8]. However, there is a concern that these metal atoms remaining in polycrystal layer become a contaminant acting as deep-level defects.…”