Enhanced photoluminescence due to lateral ordering of GeSi quantum dots on patterned Si(001) substrates
Enhanced photoluminescence due to lateral ordering of GeSi quantum dots on patterned Si(001) substrates
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DOI：
10.1088/0957-4484/21/17/175701
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发表时间：
2010-04
期刊：
影响因子：
3.5
通讯作者：
Yanwu Chen;Bingying Pan;T. Nie;Peixuan Chen;F. Lu;Zuimin Jiang;Z. Zhong
中科院分区：
文献类型：
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作者：
Yanwu Chen;Bingying Pan;T. Nie;Peixuan Chen;F. Lu;Zuimin Jiang;Z. Zhong
通过自组装技术在Si（001）衬底上制备了具有薄Si间隔层的GeSi量子点。与平坦衬底上的随机量子点相比，由周期性凹坑图案预定的GeSi量子点的横向有序性导致显著改善的尺寸均匀性。有序量子点的光致发光峰比无序量子点的发光峰更强更窄，特别是在高激发功率下。这种增强的光致发光信号归因于量子点中高的态密度和激子的均匀分布，这可以有效地抑制Auger效应和Coulomb屏蔽效应。此外，从有序量子点的PL峰的异常变窄的激发功率被观察到，这是解释与周期性堆叠GeSi量子点的分布反馈。
Multilayer ordered GeSi quantum dots (QDs) with thin Si spacers were obtained via self-assembly on pit-patterned Si(001) substrates. The lateral ordering of GeSi QDs predetermined by the periodic pit pattern results in remarkably improved size uniformity in comparison with random QDs on flat substrates. A much stronger and narrower photoluminescence (PL) peak from ordered QDs were observed than that from random ones, particularly at high excitation power. Such enhanced PL signal was attributed to the high density of states and the uniform distribution of excitons in the ordered and uniform QDs, which can efficiently suppress the Auger effect and the Coulomb screening effect. Moreover, anomalous narrowing of the PL peak from the ordered QDs with the excitation power was observed, which was explained in terms of distributed feedback associated with the periodic stacked GeSi QDs.