离子注入Si损伤分布的光谱法多层分析

应用多层模型和最优化方法,由实验测得的离子注入Si的椭偏光谱以及单晶Si和离子注入非晶Si的光学常数,能分析离子注入Si的损伤分布。我们测量了2.1—4.6eV能量范围的椭偏光谱和光学常数,建立了多层计算模型和最优化方法。在模拟分析的基础上,计算了能量为40keV,剂量分别为4×10¹³和1.4×10¹⁴cm^-2的As⁺注入Si的损伤分布,并与背散射测量的结果比较。用多层模型和最优化方法也能从光谱分析其它物理量的分布,只要这些物理量对光学性质有显著的影响,并且在测量过程中不随光子能量而改变。 关键词：     

Humidity Effects on Imaging and Nanomanipulation of Individual DNA Molecules on HOPG Surface

Single DNA molecules are aligned on highly ordered pyrolytic graphite （HOPG） surface in ambient air. It is shown that environmental humidity has a remarkable influence on the measured height of DNA by atomic force microscopy （AFM）, probably due to the conformation transition of DNA. We also demonstrate that DNA molecules deposited on HOPG surface can be ＇pushed＇ much more easily by AFM tip at high humidity than at 10W one.