Interpolating function of the strain relief of epitaxial quantum dots via an alternative morphological descriptor

Article

关键词: SHAPE TRANSITION;    GE/SI EPITAXY;    THIN-FILMS;    ISLANDS;    GROWTH;    NANOSTRUCTURES;    SURFACE;    INAS/GAAS(001);    NANOCRYSTALS;    MECHANISMS;   

DOI  :  10.1103/PhysRevB.91.195318

来源: SCIE

【 摘 要 】

Assessing the equilibrium morphologies of self-assembled heteroepitaxial quantum dots requires the estimation of their elastic (volumetric), surface, and edge energy contribution, all of them being shape dependent. Due to the size and multifaceted morphology of these islands, the estimation of the first term is typically a time-consuming or complicated task. A general rule to predict it from the sole morphologies would guarantee a precious advantage in this field. Here we present an interpolating function to fulfill this purpose for the prototypical systems of Ge/Si and InAs/GaAs. The trend is first extracted from a systematic analysis of realistic shapes observed on (001) substrates. It is then tested and corroborated for selected vicinal (tilted) substrates. Finally, the deviations due to intermixing and the underlying wetting layer are quantified. Of fundamental importance in this process is the identification of a morphological descriptor more accurate than the widely adopted aspect ratio, the limitations of which are discussed.

【 授权许可】

Free