Self-Assembling Formation of Silicon Quantum Dots

硅量子点的自组装形成

基本信息

批准号：
07455142
负责人：
HIROSE Masataka
金额：
$ 3.78万
依托单位：
HIROSHIMA UNIVERSITY
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-07455142/
关键词：
LPCVD silicon quantum dot self-assembling double barrier structure resonant tunneling tunneling current atomic force microscopy luminessence at room temperature 化学気相成長室温量子効果フォトルミネッセンス可視域発光光電子スペクトル帯電

项目摘要

Nanometer-size silicon dots were spontaneously formed on thermally-grown SiO_2/c-Si by low-pressure chemical vapor deposition (LPCVD) of pure silane (SiH_4) in the temperature range from 525 to 650ﾟC.The size distribution and the area density of Si dots were evaluated by using atomic fore microscopy (AFM) and transmission electron microscopy (TEM). The Si-dot diameter and dot height on as-grown SiO_2 are rate-limited by the thermal decomposition of SiH_4 and the cohesive action of adsorbed precursors on Si nucleation sites, respectively. It has been also found that in the Si dot formation on OH-terminated SiO_2 surface the nucleation density is dramatically enhanced and consequently the dot size and its distribution become small. The tunneling current through SiO_2/Si-dot/SiO_2 double barrier structures was measured by using a conducting AFM probe. As result, negative conductance characteristics are clearly seen at room temperature, indicating that the resonant tunneling occurs through a single Si quantum dot. It was also demonstrated that Si quantum dots covered with SiO_2 exhibit high efficiency luminescence at room temperature. No differences in luminescence peak energy and spectral shape are observable between excitations with a photon energy of 2.54and 3.81eV.It is suggested that the luminescence mainly originates from Si dots whose optical bandgap are under 2.54eV.

在525~650°C的温度范围内，采用纯硅烷(SiH_4)的低压化学气相沉积(LPCVD)在热生长的SiO_2/c-Si上自发形成纳米尺寸的硅点。其尺寸分布和面积通过使用原子前显微镜（AFM）和透射电子显微镜（TEM）评估硅点的密度，硅点直径和点高度。生长的 SiO_2 上的 SiH_4 热分解和 Si 成核位点上吸附前驱体的内聚作用分别限制了速率。还发现，在 OH 封端的 SiO_2 表面上形成 Si 点时，成核密度为通过使用SiO_2/Si-dot/SiO_2双势垒结构测量了隧道电流。结果，在室温下可以清楚地看到负电导特性，这表明谐振隧道是通过单个硅量子点发生的，并且还证明了覆盖有 SiO_2 的硅量子点在室温下表现出高效率的发光。在光子能量为 2.54 和 3.81eV 的激发之间可以观察到发光峰值能量和光谱形状的差异。这表明发光主要源自 Si 点，其光学带隙低于2.54eV。