Differential Optical Absorption Spectroscopy in Ge-Si Direct and Indirect Bandgap Superlattices

该方案是利用微分光学吸收光谱来研究和确定锗硅应变超晶格纳米结构中基本带隙的性质。第一性原理理论研究表明，直接超晶格和间接超晶格都存在，以前的实验研究也为这些计算提供了一些可信的支持。锗硅纳米结构中直接带隙行为的实验证明将为硅作为光子材料开辟一个全新的前景。提出的研究的一个主要目标是对超晶格结构和对称性以及光学性质之间的关系建立一个新的基本理解。这项工作的一个直接结果将是证明在生长过程中人为施加的晶体对称性如何用于控制半导体和其他材料的光学特性。

The proposal is to use differential optical absorption spectroscopy to study and determine the nature of the fundamental bandgap in Ge-Si strained superlattice nanostructures. First principle theoretical studies show that both direct and indirect superlattices exist, and previous experimental studies have given some credible support to these calculations. The experimental demonstration of direct bandgap behavior in Ge-Si nanostructures will open up a whole new vista for Si as a photonic material. A principal goal of the proposed research is to forge a new fundamental understanding of the relationship between superlattice structures and symmetry on one hand, and optical properties on the other. A direct result of this work will be demonstration of how crystalline symmetry, artificially- imposed during growth, can be used to control the optical propertied of semiconductors and other materials.