GaSb/GaAs quantum dot formation and demolition studied with cross-sectional scanning tunneling microscopy
GaSb/GaAs quantum dot formation and demolition studied with cross-sectional scanning tunneling microscopy
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DOI：
10.1063/1.3701614
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发表时间：
2012-04
影响因子：
4
通讯作者：
Ep Erwin Smakman;J. Garleff;R. Young;M. Hayne;P. Rambabu;P. Koenraad
中科院分区：
文献类型：
--
作者：
Ep Erwin Smakman;J. Garleff;R. Young;M. Hayne;P. Rambabu;P. Koenraad
我们用横截面扫描隧道显微镜研究了分子束外延生长的GaSb/GaAs量子点。观察到各种纳米结构作为生长参数的函数。在生长过程中，纳米结构的高局部应变场的松弛对其形成起着重要的作用。高Sb含量的锥形点上方常伴有丝状位错。利用较薄的第一盖层和较高的第二盖层生长温度有利于GaSb环的形成。在这些封顶条件下，应变驱动的Sb扩散与As/Sb交换和Sb偏析相结合，移除了纳米结构的中心，形成了一个环。没有明确形态的GaSb簇也有规律地出现，通常具有高度不均匀的结构，有时被分成碎片。
We present a cross-sectional scanning tunneling microscopy study of GaSb/GaAs quantum dots grown by molecular beam epitaxy. Various nanostructures are observed as a function of the growth parameters. During growth, relaxation of the high local strain fields of the nanostructures plays an important role in their formation. Pyramidal dots with a high Sb content are often accompanied by threading dislocations above them. GaSb ring formation is favored by the use of a thin GaAs first cap layer and a high growth temperature of the second cap layer. At these capping conditions, strain-driven Sb diffusion combined with As/Sb exchange and Sb segregation remove the center of a nanostructure, creating a ring. Clusters of GaSb without a well defined morphology also appear regularly, often with a highly inhomogeneous structure which is sometimes divided up in fragments.