CAREER: Strain Effects in Semiconductor Nanostructures

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9702725 Zaslavsky Technical CAREER Abstract The focus of the proposed research is the effect of strain on electronic properties of semiconductor nanostructures. Strain-induced effects in 1D wires and 0D dots are relatively unexplored, because the strain is strongly inhomogeneous and lacks the in-plane symmetry of the much studied 2D heterostructures. We will study two distinct classes of structures: silicon-germanium (SiGe) wires and dots, and strained III-V wires and rings fabricated by regrowth. The SiGe research will build on our recent measurements of strain relaxation and strain-induced quantization in submicron SiGe Quantum dots. The III-V structures will be fabricated by modulation-doping regrowth of in-situ patterned surfaces etched in strained heterostructures in a chamber attached directly to an MBE system. This research is relevant not only to strained nanostructure physics, but also to a number of proposed nanodevices that incorporate strained regions. In addition to graduate student training, this research will provide an ample number of semester and year-long projects for students interested in laboratory experience. %%% Nontechnical CAREER Abstract: As technology advances, semiconductor devices that underpin modern computers and lasers are becoming ever smaller. These ultrasmall structures are affected in complex ways by the mechanical strains that arise during their manufacture. We will experimentally investigate strain effects in two types of semiconductors: silicon, which is used for most electronic circuits, and gallium arsenide, which is crucial for applications that require very high speed operation or optical signals. In shedding light on strain in ultrasmall structures and gauging the promise of novel devices, this research will couple to the education of graduate and undergraduate students in semiconductor physics and technology at Brown. The education plan includes an update of semiconductor device courses and the revamping of a semester-long transistor fabrication laboratory, upon completing which students will have the background to take on semester and year-long supervised projects on sub- sections of the proposed research. ***