摘要
系统研究了在调制掺杂AlGaAs/GaAs异质结中嵌入InAs量子点后对二维电子气输运特性的影响。使用分子束外延设备生长了量子点层与二维电子气沟道距离(Tch)不同的3个样品,霍尔测试结果表明,二维电子气的电子迁移率和载流子浓度都随Tch的减小而降低。基于几何相位分析算法对部分样品的高分辨透射电镜图像进行了处理,得到了其应变分布图。结果表明,应变主要分布在量子点的周围,并延伸到了量子点的上方。该不均匀的应力场可能是除库伦散射外影响电子迁移率降低的另一个重要因素。
Effect of embedding InAs quantum dots (QDs) on the transport properties of two-dimensional gas (2-DEG) in a modulation-doped AlGaAs/GaAs heterostructure was investigated. Samples with difference thickness (Tch) from QDs layer to 2-DEG were prepared using molecular beam epitaxy. Hall measurements show that the mobility drops dramatically with the decrease of Tch, and the electron concentration shows a same trend. Strain distributions have been measured by means of geometric phase analysis of the high-resolution transmission electron microscope images. The results show that the strain is focused in the edges and above of InAs QDs which are resulted from the extended lattice distortion. And the non-uniform strain field could be another key factor for the drop of the mobility besides coulomb scattering.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2014年第6期637-642,共6页
Chinese Journal of Luminescence
基金
国家自然科学基金(61106013,11104226)
国家“863”计划(2013AA031903)
国家“973”计划(2010CB327501,2011CB925604)资助项目
关键词
量子点
二维电子气
应力
分子束外延
Drops
Electron absorption
Electron gas
Epitaxial growth
Hall mobility
Indium arsenide
Modulation
Molecular beam epitaxy
Semiconductor quantum dots
Transmission electron microscopy
Transport properties
