Construction of wide gap semiconductor nano-Quantum Dots

宽禁带半导体纳米量子点的构建

• 批准号: 10305001
• 负责人: YAO Takafumi
• 金额: $ 24.64万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10305001/
• 关键词: semiconductor quantum dot; short-wavelength optoelectronics; nano-structure; semiconducto quantum structure; exciton-based optical properties; ZnO; ZnSe; ZnCdSe; 量子ドット; ワイドギャップ半導体; 量子構造; プラズマ援用MBE; CdSe; GaN

The ultimate goal of this research is to establish the fundamental materials technology for the short-wavelength optoelectronics. To this end, we have set the following research objectives : (1) development of widegap II-VI compound semiconductors which have bandgaps ranging from the visible to uv wavelength region ; (2) development of self-organizing growth processes for those semiconductors to fabricate qunantum dots with a nano-meter size. The materials system to be investigated includes a ZnO-based materials system, ZnSe/ZnSe-based heterostructure system, and ZnCdSe/ZnSe-based heterostructure system. We have selected those material systems because of the following reasons : (1) They can cover the wavelength region from the visible to uv range ; (2) The exciton binding energies of ZnO and ZnSe/ZnSe quantum wells have large binding energies of 60 meV and 40 meV, respectively, which are much larger than the thermal energy at room temperature thereby making excitons survive at room tem … More perature or even at higher temperatures ; (3) We have been extensively working on blue-green light emitting devices of ZnCdSe/ZnSe heterostructures. I would like to mention that we have already established MBE techniques to grow those II-VI compounds, which is quite essential to lead the research project to a success.The achievements obtained in this research project can be summarized as follows : (1) We have established the molecular beam epitaxy technique for the growth high-quality widegap II-VI compound semiconductors. In addition to the already established MBE growth techniques for ZnSe, ZnSe, and ZnCdSe, we have developed (a) the oxygen-plasma assisted MBE growth technique for the growth of high-quality ZnO-based materials, (b) the fabrication techniques for heterostructures of ZnSe/ZnS, ZnCdSe/ZnSe, and ZnMgO/ZnO, and (c) the technique to control the lattice polarity of ZnO layers. Those techniques are crucial to the fabrication of well-controlled nano-scale semiconductor quantum dots. (2) We have established the self-organized fabrication processes for ZnO quantum pyramids, ZnSe/ZnS nano-scale quantum dots, and ZnCdSe/ZnSe nano-scale quantum dots. In particluar, the fabrication of ZnO quantum pyramids are the first achievements in oxide semiconductors. (3) We have discovered various novel optical properties unique to those material systems and nano-scale quantum dots. In particular, (a) The effects of localization in ZnCdSe/ZnSe quantum dots on optical properties have been elucidated, which can be utilized to enhance emisison probabilities thereby leading to the fabrication to high-bright light emitting devices. (b) The realization of induced emission from ZnO and ZnO/ZnMgO quantum structures based on excitonic mechanisms, which may open up a excitonic optical devices. (c) The first observation of spectral diffusion in ZnCdSe/ZnSe quantum dots, which may be utilized to fabricate novel optical memory devices. We hope that those achievements will contribute to the establishment of short-wavelength optoelectronics. Less

本研究的最终目标是建立短波长光电子学的基础材料技术。为此，我们确定了以下研究目标：（1）开发具有可见光至紫外光波段带隙的宽禁带II-VI族化合物半导体;（2）开发这些半导体的自组织生长过程，以制造具有纳米尺寸的量子点。所研究的材料体系包括ZnO基材料体系、ZnSe/ZnSe基异质结构体系和ZnCdSe/ZnSe基异质结构体系。我们选择这些材料系统是因为：（1）它们可以覆盖从可见光到紫外光的波长范围;（2）ZnO和ZnSe/ZnSe量子威尔斯阱的激子结合能分别为60 meV和40 meV，远大于室温下的热能，从而使激子在室温下存活 ...更多信息 （3）我们对ZnCdSe/ZnSe异质结蓝绿光发光器件进行了广泛的研究。在此我想指出的是，我们已经建立了生长这些II-VI族化合物的分子束外延技术，这是导致研究项目成功的关键，本研究项目取得的成果可以概括如下：（1）我们建立了生长高质量宽禁带II-VI族化合物半导体的分子束外延技术。除了已经建立的用于ZnSe、ZnSe和ZnCdSe的MBE生长技术之外，我们还开发了（a）用于生长高质量ZnO基材料的氧等离子体辅助MBE生长技术，（B）用于ZnSe/ZnS、ZnCdSe/ZnSe和ZnMgO/ZnO异质结构的制造技术，以及（c）控制ZnO层的晶格极性的技术。这些技术对于制造良好控制的纳米级半导体量子点至关重要。(2)我们建立了ZnO量子金字塔、ZnSe/ZnS纳米量子点和ZnCdSe/ZnSe纳米量子点的自组织制备工艺。特别是ZnO量子金字塔的制备是氧化物半导体的首次成就。(3)我们已经发现了这些材料系统和纳米尺度量子点所特有的各种新颖的光学性质。具体而言，（a）已经阐明了ZnCdSe/ZnSe量子点中的局域化对光学性质的影响，这可以用于提高发射概率，从而导致高亮度发光器件的制造。(b)基于激子机制实现ZnO和ZnO/ZnMgO量子结构的诱导发光，有望开辟激子光学器件。(c)首次观察到ZnCdSe/ZnSe量子点中的光谱扩散，这可能用于制造新型光学存储器件。我们希望，这些成就将有助于建立短波长光电子学。少

项目成果

E.Kurtz: "Properties and self-organization of CdSe : S quantum islands grown with a cadmium sulfide compouns source"J.Cryst.Growth. 214/215. 712-716 (2000)

E.Kurtz：“用硫化镉化合物源生长的 CdSe : S 量子岛的特性和自组织”J.Cryst.Growth。

M.W.Cho: ""Non-alloyed Au/p-ZnSe/p-BeTe ohmic contact layers for ZnSe-based blue-green laser diodes""Electr. Lett.. 35・20. 1740-1742 (1999)

M.W.Cho：“ZnSe 基蓝绿激光二极管的非合金 Au/p-ZnSe/p-BeTe 欧姆接触层”，Electr. 35・20 (1999)。

P.Tomasini: "Luminescence properties of ZnSe/ZnS(h11)A low dimensional structures" J.Cryst.Growth. 184/185. 343-346 (1998)

P.Tomasini：“ZnSe/ZnS(h11)A 低维结构的发光特性”J.Cryst.Growth。

N.Kumagai: "Non-destructive measurement of electron concentration in n-ZnSe by means of reflectance difference spectroscopy" J.Cryst.Growth. 184/185. 505-509 (1998)

N.Kumagai：“通过反射差光谱法无损测量 n-ZnSe 中的电子浓度”J.Cryst.Growth。

K.W.Koh: "Growth of ZnSe on misoriented GaAs(110) surface by molecular beam epitaxy" J.Cryst.Growth. 184/185. 46-50 (1998)

K.W.Koh：“通过分子束外延在取向错误的 GaAs(110) 表面上生长 ZnSe”J.Cryst.Growth。