Fundamental study of light emitting devices on silicon substrate using nanocrystalline heterostructures formed in single crystalline insulator

利用单晶绝缘体中形成的纳米晶异质结构在硅衬底上发光器件的基础研究

基本信息

批准号：
11650315
负责人：
WATANABE Masahiro
金额：
$ 2.3万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

The purpose of this study is to demonstrate light emitting properties originated from nanometer size crystals formed in single crystalline calcium fluoride (CaF_2), which is a wide band gap ionic material grown on silicon substrate. In such kind of material systems, strong quantum confinement can be expected due to large conduction band discontinuity at the heterointerface, which leads fascinating changes of electron photon interaction from the bulk material.Results obtained in this study are as follows.i) Formation technique of nanocrystalline zinc oxide (ZnO) on CaF_2/Si (111) substrate has been developed using RF sputtering followed by regrowth of CaF_2 by molecular beam epitaxy. Growth temperature, background pressure, RF power and post annealing condition was optimized.ii) Ultra-violet photoluminescence at wavelength of 380 nm and electroluminescence was observed at room temperature. Transmission electron microscopy (TEM) lattice image clearly confirmed that sharp heterointerface of CaF_2/ZnO/CaF_2 was formed. Growth condition was optimized by luminescence intensity and surface morphology.iii) Thermal annealing process in oxygen or ultra-high vacuum was introduced for improving luminescence intensity. Dependence of luminescence on annealing temperature, time, pressure was clarified.iv) Current injection luminescence was demonstrated using current restriction structure with transparent conducting ITO electrode fabricated using photolithography and dry etching. UV luminescence was clearly observed at room temperature and the luminescence was stable. From this result, nanocrystalline ZnO embedded in single crystalline CaF_2 has stable heterointerface, which is atractive for UV photonic materials on silicon substrate.

本研究的目的是证明单晶氟化钙 (CaF_2) 中形成的纳米尺寸晶体的发光特性，单晶氟化钙 (CaF_2) 是一种生长在硅基板上的宽带隙离子材料。在此类材料系统中，由于异质界面处的大导带不连续性，可以预期强量子限制，这导致体材料的电子光子相互作用发生令人着迷的变化。本研究获得的结果如下。i） CaF_2/Si (111) 基板上的纳米晶氧化锌 (ZnO) 是通过射频溅射和分子束外延再生长 CaF_2 开发的。对生长温度、背景压力、射频功率和后退火条件进行了优化。ii)在室温下观察了波长380 nm的紫外光致发光和电致发光。透射电子显微镜(TEM)晶格图像清楚地证实了CaF_2/ZnO/CaF_2的清晰异质界面的形成。通过发光强度和表面形貌优化生长条件。iii)引入氧气或超高真空中的热退火工艺以提高发光强度。阐明了发光对退火温度、时间、压力的依赖性。iv)使用具有使用光刻和干法蚀刻制造的透明导电ITO电极的电流限制结构来演示电流注入发光。室温下可清晰观察到紫外发光，且发光稳定。由此可见，嵌入单晶CaF_2中的纳米晶ZnO具有稳定的异质界面，这对硅衬底上的紫外光子材料具有吸引力。