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Control of nano-scale quantum wire structures and optocal properties of one-dimensional excitons

纳米级量子线结构和一维激子光学性质的控制

基本信息

批准号：
07455131
负责人：
SAKAKI Hiroyuki
金额：
$ 4.42万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455131/
关键词：
ridge quantum wire atomic force microscope cleaved overgrowth T-shaped GaAs quantum wire spatially resolved micro-photo luminescence one-dimensional exciton oscillator strength diamugnetic shift 量子細線一次元状態空間分解フォトルミネセンス横方向閉じ込めフォト

项目摘要

(1) Invesrigation of growth mechanism and shape control of the ridge quantum wireWe connected an ulfra high vacuum atomic force microscope to the molecular beam epitaxy system and realized an in-situ observation of the formation process of ridge quantum wire. Ridge quantum wire takes form throuhg the following process. First, (001)-(111) B facet structures appear on the mesa shaped substrate. On the border of (001)-(111) B facet, (101) surface and (112) surface also appear. As these surfaces grow, (001) surface disappears. Since Ga atoms bury vicinal facets, very smooth ridge strudture is formed. We made a successful growth of 10nm scale ridge quantum wire under the substrate temperature less than 520ﾟC.(2) Optical properties of one-dimensional exciton in the nm-scale quantum wireWe fabricated the T-shaped GaAs quantum wire by the cleaved-edge over-growth and measured spatially resolved micro photo luminescence in the magnetic fields. It was clarified that in the T-shaped quantum wire with 5nm-thick AlAs barriers the lateral confinementenergy was 38 meV and that the binding energy of one-dimentional exciton increased up to 27meV.We investigated the anisotropy of valence band from the optical anisotropy which was in good agreement with the theory. From the diamagnetic shifts, we successfully observed the dependence of the spatial extent of wave function on the width of quantum wire. It was also found that oscillator strength increased as lateral confinement was effective from the photo luminescence excitation experiment.

(1)脊状量子线生长机理及形状控制研究我们将超高真空原子力显微镜连接到分子束外延系统上，实现了对脊状量子线形成过程的现场观察。脊量子线通过以下过程形成。首先，(001)-(111)B小面结构出现在台面状衬底上。在(001)-(111)B面边界上，也出现（101）面和（112）面。随着这些表面的增长，（001）表面消失。由于Ga原子埋没了相邻的切面，形成了非常光滑的脊状结构。我们在低于520℃的衬底温度下成功地生长了10nm尺度的脊量子线。(2)纳米尺度量子线中一维激子的光学性质我们采用剪边过生长法制备了t形GaAs量子线，并测量了其在磁场中的空间分辨微光发光。结果表明，在具有5nm厚AlAs障壁的t型量子线中，横向束缚能为38mev，一维激子的结合能增加到27meV。我们从光学各向异性的角度研究了价带的各向异性，结果与理论一致。从反磁位移中，我们成功地观察到波函数的空间范围与量子线宽度的依赖关系。光致发光激发实验还发现，由于侧向约束有效，振子强度增加。