摘要
采用水淬法制备出块状非晶态硒,通过非晶晶化法获得了六方晶型结构的、晶粒尺寸为6—45nm的块状纳米晶硒,X射线衍射及热分析研究表明非晶态硒向纳米晶硒的转变是由一步晶化完成的,激活能为54—60kJ/mol.并证实了非晶硒的短程序与六方晶型硒相同以及非晶硒的无规线团结构.根据不同方向的晶粒尺寸与晶化温度的关系,发现沿c轴的生长速率大于沿a轴的生长速率.采用无规线团形的分子链在晶界处折叠或延伸到相邻晶粒中的晶化机制解释了晶化过程中激活能低和生长速率沿c轴方向较大的实验结果.
A bulk amorphous selenium (a-Se) was made by quenching the liquid Se into water. Bulk nanocrystalline selenium (nc-Se) samples with hexagonal structure and grain sizes ranging from 6 nm to 45 nm were obtained by crystallizing the as-quenched amorphous selenium. X-ray diffraction and DSC analyses show that the transition from a-Se to nc-Se is a one-step crystal lization process, the activation energy of which is 54-60 kJ/mol, It was confirmed that the topological short-range order of the a-Se is similar to hexagonal selenium and resembles random-coil structure of polymeric organic glasses. It is deduced from the dependence of grain sizes on the lattice orientations that the growth rate along c-axis is higher than that along a-axis. The low activation energy and high growth rate along c-axis in the transition pro-cess from the a-Se to the nc-Se can be explained with the crystallization microme-chanism of chains folding or stretching to adiacent grains at the grain boundaries.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
1995年第1期109-114,共6页
Acta Physica Sinica
