Mn^+注入GaAs中Ga-Mn二十面体准晶的形成

Ga Mn icosahedral quasicrystal particles fabricated by Mn + implantation in GaAs

利用选区电子衍射及明暗场电子衍射成像技术，在Ｍｎ＋注入ＧａＡｓ及随后退火的样品表层发现有二十面体准晶颗粒形成．能谱及电子能量损失谱分析表明，这些粒子不含Ａｓ，由Ｇａ和Ｍｎ元素组成，约含５０ａｔ％的Ｍｎ；其结构具有五次对称性和非周期分布的电子衍射斑点．这些具有２／ｍ３５对称性的ＧａＭｎ准晶粒子同具有闪锌矿结构的ＧａＡｓ基体之间具有确定的取向关系：ｉ－５∥〔１１０〕ＧａＡｓ；ｉ－３∥〔１１１〕ＧａＡｓ；ｉ－２∥〔１２１〕ＧａＡｓ．用磁力显微镜分析发现这些粒子中的许多粒子具有铁磁性．

For the first time, Ga Mn icosahedral (IQC) particles have been found in Mn + implanted GaAs. GaAs wafers were implanted with Mn + at 80 keV with total dose of 2×10 17 /cm 2, then annealed at 830℃ for 90 seconds. The electron diffraction patterns of these particles show quasicrystalline features and are quite the same as IQC patterns observed in aluminum alloys. Moreover, there is a definite orientation relationship between these IQC particles and the GaAs matrix: i 5 ∥ 110 GaAs ; i 3 ∥ 11 1 GaAs and i 2∥ 12 1 GaAs . The IQC particles analyzed by electron probe show that the particles are composited of Ga and Mn(50 at%). Magnetic force microscope observation shew that about 70% of these submicron particles are magnetic.