Control of symmetric properties of metamorphic Ino.27Ga0.73As layers by substrate misorientation

• Published in: 中国物理B：英文版 2016 (3), p.408-413
• Main Author: 于淑珍 董建荣 孙玉润 李奎龙 曾徐路 赵勇明 杨辉
• Format: Article
• Language: English
• Subjects: GaAs（001）; 取向控制; 变质; 外延材料; 对称性质; 电子输运性质; 衬底; 透射电子显微镜
• ISSN: 1674-1056; 2058-3834

Asymmetry in dislocation density and strain relaxation has a significant impact on device performance since it leads to anisotropic electron transport in metamorphic materials. So it is preferred to obtain metamorphic materials with symmetric properties. In this paper, we grew metamorphic Ino.27Gao.73As epilayers with symmetric low threading dislocation density and symmetric strain relaxation in two （110） directions using InA1GaAs buffer layers on 7° misoriented GaAs （001） substrates. To understand the control mechanism of symmetric properties of Ino.27Gao.73As layers by the substrate miscut angles, Ino.27Gao.73As grown on 2° and 15° misoriented substrates were also characterized as reference by atomic force microscopy, transmission electron microscopy, and high resolution triple axis x-ray diffraction. The phase separation and interaction of 60° misfit dislocations were found to be the reasons for asymmetry properties of Ino.27Gao33As grown on 2° and 15° substrates, respectively. Photoluminescence results proved that the Ino.27G°ao.73As with symmetric properties has better optical properties than the Ino.27Gao.73As with asymmetric properties at room temperature. These results imply that high quality metamorphic Ino.27Gao.73As can be achieved with controllable isotropic electron transport property.