Niu Lang, Hao Zhibiao, Hu Jiannan, Hu Yibin, Wang Lai, Luo Yi
Department of Electronic Engineering, Tsinghua National Laboratory for Information Science and Technology, Tsinghua University, Beijing 100084, People's Republic of China.
Nanoscale Res Lett. 2011 Dec 2;6(1):611. doi: 10.1186/1556-276X-6-611.
The quantum-confined stark effect induced by polarization has significant effects on the optical properties of nitride heterostructures. In order to improve the emission efficiency of GaN/AlN quantum dots [QDs], a novel epitaxial structure is proposed: a partially relaxed GaN layer followed by an AlN spacer layer is inserted before the growth of GaN QDs. GaN/AlN QD samples with the proposed structure are grown by molecular beam epitaxy. The results show that by choosing a proper AlN spacer thickness to control the strain in GaN QDs, the internal quantum efficiencies have been improved from 30.7% to 66.5% and from 5.8% to 13.5% for QDs emitting violet and green lights, respectively.
极化诱导的量子限制斯塔克效应（QCSE）对氮化物异质结构的光学性质有显著影响。为了提高GaN/AlN量子点（QD）的发光效率，提出了一种新型外延结构：在生长GaN量子点之前，先插入一个部分弛豫的GaN层，然后是一个AlN间隔层。采用分子束外延法生长了具有该结构的GaN/AlN量子点样品。结果表明，通过选择合适的AlN间隔层厚度来控制GaN量子点中的应变，对于发射紫光和绿光的量子点，其内部量子效率分别从30.7%提高到66.5%和从5.8%提高到13.5%。
