Effects of Surface Structure on Ordering in III/V Systems

9320541斯特林费罗拟议的研究针对III-V半导体合金在外延生长过程中与原子尺度有序化相关的基本表面过程。这种有序化现象是最近才发现的，而且非常有意义，因为有序化被认为与生长过程中发生的表面过程密切相关，而且有序化改变了基本的材料性质，如无序合金的带隙。最近的工作表明，表面重建和表面上台阶的运动控制着有序化过程。不幸的是，导致排序模型的许多观察都是间接的。拟议的研究试图将表面特征，如重建和步骤与排序直接联系起来，并同时监测所得到的材料的光学和电学性质。%目前，对气相外延晶体生长过程中的表面结构的详细了解普遍较差。建议的研究将大大有助于我们对外延生长过程的基本理解、控制和总体能力的提高。这项研究还具有重大的技术相关性；这项研究的结果预计将在开发和实现先进的电子和光子设备概念方面以各种方式有用。这可能有助于实现光子和载流子的限制，以及有意缩小红外光子器件的能带宽度。有序化还有望通过消除合金散射来增强自由载流子迁移率。这项研究预计将对电信、信息处理和高速计算等一般领域产生积极影响。***

9320541 Stringfellow The proposed research addresses fundamental surface processes related to atomic scale ordering in III-V semiconductor alloys during epitaxial growth. This ordering phenomenon has only recently been discovered, and is of great basic interest since ordering is thought to be intimately connected with the surface processes occurring during growth, and because ordering changes fundamental materials properties such as the band gap of the disordered alloy. Recent work has indicated that surface reconstruction and the motion of steps on the surface control the ordering process. Unfortunately, many of the observations leading to the ordering models are indirect. The proposed research attempts to directly relate surface features such as reconstruction and steps to ordering, and to simultaneously monitor optical and electrical properties of the resulting material. %%% At present, detailed understanding of the surface structure during vapor phase epitaxial crystal growth is generally poor. The proposed research will significantly benefit our basic understanding, control, and general ability to improve epitaxial growth processes. The research also has significant technological relevance; results from this research are expected to be useful in a variety of ways in developing and bringing advanced electronic and photonic device concepts to fruition. It will likely be useful for achieving photon and carrier confinement, and for the intentional reduction of the energy band gap for infrared photonic devices. Ordering is also expected to lead to enhancement of free carrier mobilities by eliminating alloy scattering. The research is expected to have a positive impact on the general areas of telecommunications, information processing; and high speed computing. ***