Self-assembly of InAs quantum dots on GaAs（O01） by molecular beam epitaxy  

作　　者：Ju Wu Peng Jin 

机构地区：[1]Key Laboratory of Semiconductor Materials Science and Beijing Key Laboratory ofLow-dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China

出　　处：《Frontiers of physics》2015年第1期7-58,共52页物理学前沿（英文版）

基　　金：The work was supported by the National Basic Research Program of China （Grant No. 2006CB604904） and the National Natural Science Foundation of China （Grant Nos. 61274072, 60976057, 60876086 and 60776037）.

摘　　要：Currently, the nature of self-assembly of three-dimensional epitaxial islands or quantum dots （QDs） in a lattice-mismatched heteroepitaxial growth system, such as InAs/GaAs（001） and Ge/Si（001） as fabricated by molecular beam epitaxy （MBE）, is still puzzling. The purpose of this article is to discuss how the self-assembly of InAs QDs in MBE InAs/GaAs（001） should be properly understood in atomic scale. First, the conventional kinetic theories that have traditionally been used to interpret QD self-assembly in heteroepitaxial growth with a significant lattice mismatch are reviewed briefly by examining the literature of the past two decades. Second, based on their own experimental data, the authors point out that InAs QD self-assembly can proceed in distinctly different kinetic ways depending on the growth conditions and so cannot be framed within a universal kinetic theory, and, furthermore, that the process may be transient, or the time required for a QD to grow to maturity may be significantly short, which is obviously inconsistent with conventional kinetic the- ories. Third, the authors point out that, in all of these conventional theories, two well-established experimental observations have been overlooked： i） A large number of ＂floating＂ indium atoms are present on the growing surface in MBE InAs/GaAs（001）; ii） an elastically strained InAs film on the GaAs（001） substrate should be mechanically unstable. These two well-established experimental facts may be highly relevant and should be taken into account in interpreting InAs QD formation. Finally, the authors speculate that the formation of an InAs QD is more likely to be a collective event involving a large number of both indium and arsenic atoms simultaneously or, alternatively, a morphological/structural transformation in which a single atomic InAs sheet is transformed into a three-dimensional InAs island, accompanied by the rehybridization from the sp2-bonded to sp3- bonded atomic configuration of both indium and arsenic Currently, the nature of self-assembly of three-dimensional epitaxial islands or quantum dots （QDs） in a lattice-mismatched heteroepitaxial growth system, such as InAs/GaAs（001） and Ge/Si（001） as fabricated by molecular beam epitaxy （MBE）, is still puzzling. The purpose of this article is to discuss how the self-assembly of InAs QDs in MBE InAs/GaAs（001） should be properly understood in atomic scale. First, the conventional kinetic theories that have traditionally been used to interpret QD self-assembly in heteroepitaxial growth with a significant lattice mismatch are reviewed briefly by examining the literature of the past two decades. Second, based on their own experimental data, the authors point out that InAs QD self-assembly can proceed in distinctly different kinetic ways depending on the growth conditions and so cannot be framed within a universal kinetic theory, and, furthermore, that the process may be transient, or the time required for a QD to grow to maturity may be significantly short, which is obviously inconsistent with conventional kinetic the- ories. Third, the authors point out that, in all of these conventional theories, two well-established experimental observations have been overlooked： i） A large number of ＂floating＂ indium atoms are present on the growing surface in MBE InAs/GaAs（001）; ii） an elastically strained InAs film on the GaAs（001） substrate should be mechanically unstable. These two well-established experimental facts may be highly relevant and should be taken into account in interpreting InAs QD formation. Finally, the authors speculate that the formation of an InAs QD is more likely to be a collective event involving a large number of both indium and arsenic atoms simultaneously or, alternatively, a morphological/structural transformation in which a single atomic InAs sheet is transformed into a three-dimensional InAs island, accompanied by the rehybridization from the sp2-bonded to sp3- bonded atomic configuration of both indium and arsenic

关 键 词：molecular beam epitaxy InAs quantum dots 

分 类 号：TN304.23[电子电信—物理电子学] TN304.205