Development of Novel Instrumentation for the Growth of Low Dimensional Structures Using Molecular Beam Epitaxy

9871210梅诺尼随着量子限制的增加，能够定制低维半导体结构的光学和电学特性，这使得这些结构对于光电子器件的设计具有吸引力。制造限制载流子在一个方向或原子团簇内移动的纳米结构，如分别在量子线和量子点中移动，是一项技术挑战。PI建议开发用于低维结构生长的新型仪器，其中包括在分子束外延生长III-V异质结构过程中对原子物种的光学操纵。激光束将被非侵入性地引入分子束外延室。反向传播的激光产生的辐射力将被用来将III族物种聚焦成一系列线或点，以形成特征尺寸小于100 nm的周期性量子线或量子点结构。这将在生长平面上产生一个组成调制，由富含III物种的区域组成，这些区域被已经耗尽III物种的区域隔开。这种成分调制将限制载流子在生长平面上的一个或两个方向，这取决于是使用一个还是两个相互垂直的驻波来聚焦原子束。在生长方向上的载流子限制将通过将成分调制层与适当组成的限制层夹在中间来实现。该仪器将在不显著改变生长条件的情况下，为传统的分子束外延生长过程增加一种全新的能力。拟议中的仪器将允许演示一种生长方法，该方法将对纳米结构的位置和大小提供前所未有的控制*

9871210 Menoni The ability to tailor the optical and electronic properties of low dimensional semiconductor structures with increased quantum confinement makes these structures attractive candidates for the design of optoelectronic devices. Fabrication of nanostructures that constrain the carriers to move in either one direction or within atomic clusters, as in quantum wires and quantum dots respectively, is a technological challenge. The PIs propose to develop novel instrumentation for the growth of low dimensional structures that incorporates optical manipulation of atomic species during the molecular beam epitaxy growth of III-V heterostructures. Laser beams will be introduced noninvasively into the MBE chamber. The radiation force generated by counter-propagating laser beams will be used to focus the Group III specie into an array of lines or dots to form periodic quantum wire or quantum dot structures with sub- 100nm feature size. This will create a composition modulation in the growth plane consisting of regions that are rich in the III-specie separated by regions that have been depleted of the III-specie. Such composition modulation will confine the carriers in either one or two directions in the plane of growth, depending on whether one or two mutually perpendicular standing waves of light are used to focus the atomic beam. Carrier confinement in the growth direction will be accomplished by sandwiching the composition-modulated layer with confinement layers of appropriate composition. The instrument will add a radically new capability to conventional MBE growth process without significantly altering the growth conditions. The proposed instrumentation will allow for the demonstration of a growth method that will provide unprecedented control in the location and size of the nanostructures ***