Characterization of structrual and optical properties of Si1 -xGex nanocrystal produced by laser-induced pyrolysis and by ion implantation

激光诱导热解和离子注入产生的 Si1-xGex 纳米晶体的结构和光学性质表征

• 批准号: 32520454
• 负责人: Professor Dr. Friedrich Huisken
• 金额: --
• 依托单位: Arbeitsgruppe Ionenstrahlphysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/32520454?language=en
• 关键词: Characterization; structrual; optical; properties; Si1

The first objective of the present project is to produce Si1 ¿ xGex nanocrystals (Si1 ¿ xGex -nc), or quantum dots covering the entire range from x = 0 to x = 1, under original conditions and by means which have not yet been exploited: (1) in the gas phase by laser-induced pyrolysis of a mixture of silane (SiH4) and germane (GeH4), and (2) in matrices by sequential ion (Si+ and Ge+) implantation and postannealing. The nanocrystals prepared in process (1) will be selected in size and deposited on substrates in the form of thin films, whereas those prepared by method (2) will be embedded in solid matrices (mainly silica). Applying both techniques and varying the process parameters, Si1 - xGex nanocrystals with different Si/Ge relative concentrations and with various surroundings, passivating oxide shell in (1) or matrix in (2), will be produced. In the second step, the structure and composition of the quantum dots will be characterized by electron microscopy as well as IR and Raman spectroscopy. We will explore how the crystal structure varies with size and composition and whether phase transitions can be observed. Finally, constituting the most important objective of the proposal, we will investigate the photoluminescence (PL) properties of the Si1 - xGex quantum dots as a function of size and composition. The studies will address the question whether the PL results from radiative recombination of charge carriers in quantum-confined systems and to what extent other mechanisms such as interface defects are operative. Quantum-confined PL appears most interesting since it allows to vary the wavelength by varying the size. As far as optoelectronic applications are concerned, it is our aim to verify the improved PL properties of Si nanocrystals upon Ge-doping as predicted by theory.

当前项目的首要目标是生产 Si1 ¿ xGex 纳米晶体 (Si1 ¿ xGex -nc) 或覆盖从 x = 0 到 x = 1 整个范围的量子点，在原始条件下并通过尚未开发的方法：(1) 在气相中通过激光诱导硅烷 (SiH4) 和锗烷 (GeH4) 的混合物的热解，以及 (2) 通过顺序离子（Si+ 和 Ge+）注入基质，以及方法(1)中制备的纳米晶体将选择尺寸并以薄膜的形式沉积在基底上，而方法(2)中制备的纳米晶体将被嵌入到固体基质中(主要是二氧化硅)。根据工艺参数，将产生具有不同Si/Ge相对浓度和不同环境的Si1-xGex纳米晶体，（1）中的钝化氧化物壳或（2）中的基体。第二步，通过电子显微镜以及红外和拉曼光谱来表征量子点的结构和成分，我们将探索晶体结构如何随尺寸和成分变化以及是否可以观察到相变。该提案最重要的目标是，我们将研究 Si1 - xGex 量子点的光致发光 (PL) 特性作为尺寸和成分的函数。这些研究将解决 PL 是否由辐射产生的问题。量子限制系统中载流子的重组以及界面缺陷等其他机制的发挥作用似乎最有趣，因为就光电应用而言，它允许通过改变尺寸来改变波长。我们的目的是验证硅纳米晶体在掺杂 Ge 后的 PL 性能是否如理论预测的那样得到改善。