Morphology and growth of capped Ge/Si quantum dots

作者：Yacoby Yizhak; Elfassy Naomi; Ray Samit K; Singha Raj K; Das Samaresh; Cohen Eyal; Yochelis Shira; Clarke Roy; Paltiel Yossi^*

来源：Journal of Nanoparticle Research, 2013, 15(5): 1608.

DOI：10.1007/s11051-013-1608-3

• Nano-crystals
• Quantum dots
• X-ray crystallography
• Self-assembly
• MBE

The morphology, atomic structure, and chemical composition of small (4 nm average height and 20 nm average diameter), dense capped MBE-grown Ge/Si quantum dots are studied using an energy-differential extension of the direct X-ray phasing method, COBRA. Our results lead to the following conclusions: (i) the quantum dot system has a partial wetting layer; (ii) in the lower parts of the dots, the Ge content is small and increases toward the top; and (iii) the contact angle between the dots and the substrate is acute, consistent with the presence of a wetting layer. A growth mechanism compatible with these findings is proposed.

• 出版日期2013-5