Spontaneous Formation of Identical Collections of Nanostructures During Semiconductor Heteroepitaxy

9402184将开展德鲁克研究，以便对与直接外延沉积相关的过程有一个基本的了解，从而在Ge/Si(100)异质外延过程中自发形成一组相同的、无缺陷的纳米结构。原位(低能电子显微镜、扫描隧道显微镜和超高真空扫描透射电子显微镜)和非原位(透射电子显微镜)显微镜的独特组合将被用来评估这些纳米结构的尺寸、均匀性、面密度和空间分布。通过改变沉积参数来改变生长表面上可移动的吸附原子的浓度(过饱和度)，从而调整均匀的点集合的大小。这些纳米结构的大小将通过Ge中的玻尔半径(约10 nm)进行调节，以研究量子限制的影响。使用直接外延沉积允许在半导体表面上原位形成目标结构，最重要的是，在单个步骤中形成。本计划的主要目标是对Ge/Si量子点的外延生长、加工和性质有一个基本的了解，以便它们能够被用于实现各种先进的电子和光子器件。该计划的一个重要特点是在材料和工艺研究的基础和技术方面对研究生和本科生进行培训。这项研究将有助于提高用于计算、信息处理和电信的先进器件和集成电路的综合性能。***

9402184 Drucker Research will be carried out to develop a fundamental understanding of the processes associated with direct epitaxial deposition to spontaneously form a collection of identical, defect free nanostructures during Ge/Si(100) heteroepitaxy. A unique combination of both in situ (low energy electron microscopy, scanning tunneling microscopy and ultrahigh vacuum scanning transmission electron microscopy) and ex situ (transmission electron microscopy) microscopy will be used to asses the size, uniformity, areal density and spatial distribution of these nanostructures. Tuning the size of uniform collections of dots will be investigated by varying the concentration of mobile adatoms (supersaturation) on the growth surface through changes in deposition parameters. The size of these nanostructures will be tuned through the Bohr radius in Ge, about 10 nm, to investigate the effects of quantum confinement. Use of direct epitaxial deposition allows formation of the target structures on a semiconductor surface, in situ and, most importantly, in a single step. %%% The primary goal of this program is to develop a fundamental-understanding of the epitaxial growth, processing, and properties of Ge/Si quantum dots so that they can be exploited in the realization of a variety of advanced electronic and photonic devices. An important feature of the program is the training of graduate and undergraduate students in a fundamentally and technologically significant area of materials and processing research. This research will contribute to improving the general performance of advanced devices and integrated circuits used in computing, information processing, and telecommunications. ***