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

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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 ***