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采用表面钝化和MOCVD低温生长在蓝宝石 (0 0 0 1)面 (即C面 )和蓝宝石 (110 2 )面 (即R面 )上形成了InGaN量子点 ,并构成了该量子点的多层结构。原子力显微镜测试的结果表明单层InGaN量子点平均宽约 40nm ,高约15nm ;而多层量子点上层的量子点则比单层的InGaN量子点大。R面蓝宝石衬底上生长的InGaN量子点和C面蓝宝石衬底上生长的InGaN量子点相比 ,其PL谱不仅强度高 ,而且没有多峰结构。这是由于在C面蓝宝石衬底上生长的InGaN/GaN多层量子点沿生长方向 [0 0 0 1]存在较强的内建电场 ,而在R面蓝宝石衬底上得到的多层量子点沿着生长方向 [112 0 ]没有内建电场。InGaN量子点变温光致发光 (PL)谱研究发现量子点相关的峰有快速红移现象 ,这是量子点系统所特有的PL谱特征。用在R面蓝宝石上生长的InGaN量子点作有源层有望避免内建电场的影响 ,得到高量子效率且发光波长稳定的发光器件。
The InGaN QDs were formed on the sapphire (0 0 0 1) plane (ie, C plane) and the sapphire (110 2) plane (ie, R plane) by surface passivation and MOCVD cryogenic growth. structure. Atomic force microscopy results show that single quantum InGaN quantum dots have an average width of about 40 nm and a height of about 15 nm. The quantum dots of the upper quantum dot are larger than the single quantum dots of InGaN quantum dots. The PL spectra of InGaN quantum dots grown on R-plane sapphire substrate and InGaN quantum dots grown on C-plane sapphire substrate are not only high in intensity but also have no multimodal structure. This is because the InGaN / GaN multilayer quantum dots grown on a C-plane sapphire substrate have a stronger built-in electric field along the growth direction [0 0 0 1], while the multi-layer quantum dots obtained on the R plane sapphire substrate There is no built-in electric field along the growth direction [112 0]. InGaN QD photoluminescence (PL) spectroscopy study found that the QDs have a fast redshift, which is unique to the quantum dot system PL spectral features. It is expected that the InGaN QDs grown on R-plane sapphire as the active layer can avoid the influence of the built-in electric field to obtain a light-emitting device with high quantum efficiency and stable light-emitting wavelength.