A RESEARCH ON QUANTUM DOT BASED MATERIAL FOR WAVELENGTH-DIVISION-MULTIPLICATION MEMORY APPLICATIONS

现在有可能形成量子点，其中电子以其离散能级的形式显示其波性。然而，到目前为止，这些点的大小并不统一。基于量子点对与其尺寸相对应的特定波长光的响应特性，本研究旨在将非均匀量子点用于分波倍增光存储。我们发现了分子束外延（MBE）生长的InAs/GaAs自组装量子点（SAQDs）的尺寸分布和位置分布的尺度函数。这表明控制圆点形成的机制可以用一幅相当简单的图来描述。我们研究了利用隧道效应提高记忆持续时间的可能性，并证实了来自InAlAs SAQDs的电子通过AlGaAs隧道势垒到AlAs层的隧道效应。此外，我们展示了使用堆叠技术增加点的有效密度的可能性。采用离子通道法研究了InAs/GaAs SAQD的晶格变形和原子扩散。结果表明，Ga的扩散与InAs的覆盖程度密切相关，并确定了两种生长模式：一种是大点的Ga扩散较小，另一种是小点的Ga扩散明显。

Now it is possible to form quantum dots in which electrons show its wavenature as their discrete energy levels. So far, however, the size of the dots is not uniform. This study aim at using those inhomogeneous quantum dots for wave-division-multiplication optical memory based on the fact that quantum dots respond to light with a specific wavelength corresponding to its size.We discovered scaling functions of the size distribution and the position distribution of the InAs/GaAs self-assembled quantum dots(SAQDs)grown by molecular beam epitaxy(MBE). This indicates that the mechanism governing the formation of the dots is described by a rather simple picture.We studied a possibility to enhance the memory duration using tunneling effect, and confirmed the tunneling of the electrons from InAlAs SAQDs through an AlGaAs tunneling barrier to the AlAs layer. Also, we showed possibilities to increase the effective density of dots using a stacking technique.The lattice deformation and atomic diffusion of the InAs/GaAs SAQD were studied by ion channeling method. It was shown that the Ga diffusion depended strongly on the InAs coverage and that there were two regions of growth modes identified : one with larger dots with little Ga diffusion and the other with smaller dots with evident Ga diffusion.