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Self-assembled quantum dots based on use of dilute nitride semiconductors

基于稀氮化物半导体的自组装量子点

基本信息

批准号：
17360135
负责人：
OKADA Yoshitaka
金额：
$ 6.09万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

First, self-assembled Ga_xIn_<1-x> N_yAs_<l-y> quantum dot structures fabricated on GaAs (001) substrates have been studied with atomic-Hydrogen assisted molecular beam epitaxy and a radio frequency nitrogen plasma source. The GaInNAs quantum dots are promising for extending emission wavelengths from 1. 3 to 1.55 um and beyond. We succeeded in achieving high densities on the order of 1. 1x10^<11> cm^<-2> for Ga_<0.53> In_<0.47> No_<0.02> As_<0.98> quantum dots on GaAs (001). Further, we studied the effect of H_2 flux on both the growth dynamics and the optical properties, and found that an optimum H_2 flux rate for Ga_<0.53> In_<0.47> No_<0.02> As_<0.98> quantum dot growth in our system is at around 0.6sccm. These results are attributed to originate from improvement of crystal quality of GaInNAs quantum dots by irradiation of atomic H.Next, we investigated a growth technique to fabricate multiple-stacked InAs self-assembled quantum dots on GaAs (001) substrates. The stacking of dots is achieved by strain compensation technique, in which GaNAs is used as a spacer layer to bury a quantum dot layer. No dislocations are observed even after 20 layers of stacking, and the area density of quantum dots amounted to the order of 10^<12> cm^<-2>. From photoluminescence measurements, a single emission peak from quantum dots is clearly observed at around 1200 nm at room temperature. Further, the emission peak energy straightforwardly shifts to longer wavelengths with increasing N composition in GaNAs spacer layer due to the lowering the quantum confinement energy or barrier height.

首先，利用原子氢辅助分子束外延和射频氮等离子体源研究了在GaAs(001)衬底上自组装的Ga_xIn_y&gt；N_yAs_y&gt；L-y&gt；量子点结构。GaInNAs量子点有望将发射波长从1.3微米扩展到1.55微米甚至更远。我们成功地获得了GaAs(001)上Ga0.53&gt；In；0.47；No_&lt；0.02&gt；As_&lt；0.98&gt；量子点密度达1.1×10~(-1)~(-2)量级的高密度。此外，我们还研究了氢气流量对量子点生长动力学和光学性质的影响，发现在我们的系统中，生长Ga0.53&gt；In0.47&gt；0.02&gt；As_&lt；0.98&gt；量子点的最佳氢流量为0.6sccm左右。这些结果归因于H原子辐照改善了GaInNAs量子点的晶体质量。接下来，我们研究了一种在GaAs(001)衬底上生长多层InAs自组装量子点的技术。点的堆叠是通过应变补偿技术实现的，在应变补偿技术中，GaAs被用作隔离层来掩埋量子点层。即使经过20层堆积也没有观察到位错，量子点的面密度达到10^&lt；12&gt；cm^&lt；-2&gt；通过光致发光测量，在室温下，量子点在1200 nm附近清晰地观察到一个单一的发射峰。此外，由于量子限制能或势垒高度的降低，随着GaNAS隔离层中N组分的增加，发射峰值能量直接向更长的波长移动。