基于分子束外延技术可控制备Bi原子团簇的研究

Research on the controllable preparation of Bi atomic clusters based on molecular beam epitaxy technology

本研究基于分子束外延(MBE)技术在Si(111)衬底表面成功制备金属Bi原子团簇.首先,分别在100℃、125℃、150℃、175℃、200℃的生长温度下,制备了大小均一、密度不同的Bi原子团簇.实验结果表明,可以通过改变生长温度来精细控制Bi原子团簇的密度,当温度升高100℃,密度从1.05×10^(11)cm^(-2)降低至2.5×10^(7)cm^(-2),实现对团簇密度4个数量级的可控调节,并且发现Bi原子团簇密度对生长温度的依赖性符合经典成核理论.其次,分别在10 s、15 s、20 s的沉积时长下,制备了密度相同、尺寸各异的Bi原子团簇.实验结果表明,可以通过改变沉积时长来精细控制Bi原子团簇的尺寸:当沉积时长增加10 s,高度和直径分别从8.5 nm和65 nm增大到13.7 nm和100 nm,实现对团簇尺寸在10 nm高度、80 nm直径范围的可控调节,并且发现Bi原子团簇尺寸对沉积时长的依赖性符合晶体生长动力学.与分子束外延制备传统的Ⅲ族(Al,Ga,In)原子团簇做对比,这些结果可以为制备Ⅴ族原子团簇提供实验参考和指导,从而促进纳米级含Bi材料的制备.

This study successfully prepared metal Bi atomic clusters on Si(111)substrate surfaces using molecular beam epitaxy(MBE)technique.Firstly,Bi atomic clusters with uniform size but different densities were prepared at growth temperatures of 100℃,125℃,150℃,175℃,and 200℃.Experimental results showed that the density of Bi atomic clusters could be finely controlled by varying the growth temperature.When the temperature increased by 100℃,the density decreased from 1.05×10^(11) cm^(-2) to 2.5×10^(7) cm^(-2),achieving a controllable adjustment of cluster density by four orders of magnitude.It was also found that the dependence of Bi atomic cluster density on growth temperature conformed to the classical nucleation theory.Secondly,Bi atomic clusters with the same density but different sizes were prepared at deposition times of 10 s,15 s,and 20 s.Experimental results showed that the size of Bi atomic clusters could be finely controlled by changing the deposition time.When the deposition time increased by 10 s,the height and diameter increased from 8.5 nm and 65 nm to 13.7 nm and 100 nm,respectively,enabling a controllable adjustment of cluster size within the range of 10 nm in height and 80 nm in diameter.The dependence of Bi atomic cluster size on deposition time was found to follow crystal growth kinetics.By comparing with the preparation of conventional Group Ⅲ(Al,Ga,In)atomic clusters,these results can provide experimental references and guidance for the preparation of Group Ⅴ atomic clusters,thereby promoting the fabrication of nanoscale materials containing Bi.