Instituto Superior Técnico, Campus Tecnológico e Nuclear, Universidade de Lisboa, 2695-066 Bobadela LRS, Portugal.
Nanotechnology. 2013 Dec 20;24(50):505717. doi: 10.1088/0957-4484/24/50/505717. Epub 2013 Nov 27.
Ion-induced intermixing and damage is evaluated in GaN/AlN superlattices of quantum dots (QDs) and quantum wells (QWs) using 100 keV Ar(+) implantation at low temperature (15 K). Despite the similar damage build up at low fluences, a significant increase of the damage accumulation takes place for QDs at high fluences. Elemental depth profiles were fitted with a diffusion model, revealing the higher intermixing efficiency in QD superlattices, significantly higher than for QWs. The scaling of diffusion length with the local fluence and defect concentration is understood on the basis of cascade mixing and migration of defects in the cation sublattice. The selective intermixing/damage of QDs is explained by the promotion of lateral diffusion mechanisms that result in smooth interfaces, as well as by an enhanced diffusivity due to the characteristic strain distribution in QD superlattices.
采用 100keV Ar(+)低温（15K）注入技术，评估了 GaN/AlN 量子点（QD）和量子阱（QW）超晶格中的离子诱导混合和损伤。尽管在低剂量下，损伤积累相似，但在高剂量下，QD 的损伤积累会显著增加。元素深度分布采用扩散模型拟合，表明 QD 超晶格的混合效率更高，明显高于 QW。基于级联混合和阳离子亚晶格中缺陷的迁移，根据局部剂量和缺陷浓度对扩散长度进行了缩放。QD 的选择性混合/损伤可以通过促进横向扩散机制来解释，这些机制会导致平滑的界面，以及由于 QD 超晶格中的特征应变分布而导致的扩散性增强。
