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Title:Fabrication and characterization of compound semiconductor nanostructures
Author(s):Panepucci, Roberto Ricardo
Doctoral Committee Chair(s):Adesida, Ilesanmi
Department / Program:Electrical and Computer Engineering
Discipline:Electrical and Computer Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Engineering, Electronics and Electrical
Physics, Condensed Matter
Engineering, Materials Science
Abstract:Semiconductor optoelectronic devices are expected to have their performance improved by the use of quantum confinement in the active region with sizes in the range of tenths of nanometers. The decrease in volume of the active region and the modification in the density of states in quantum structures is predicted to improve the threshold current, increase the modulation bandwidth, yield narrower spectral linewidths, and reduce temperature sensitivity in semiconductor lasers. This thesis reports the development and characterization of several fabrication techniques of compound semiconductor nanostructures on $\rm In\sb{0.53}Ga\sb{0.47}As/InP$ and $\rm In\sb{x}Ga\sb{1-x}As/GaAs$, and the optical properties of the fabricated structures. Requirements on the electron beam lithography for each fabrication technique are presented, with emphasis on the capabilities of the lithography tool and parameters of the resist material, in particular, ZEP-520 and bilayers of PMMA. Photoluminescence measurements at 5 K were used to characterize the optical quality of the samples.
Fabrication of quantum wires and dots using highly anisotropic reactive ion etching of $\rm In\sb{0.53}Ga\sb{0.47}As/InP$ with $\rm CH\sb4{:}H\sb2$ plasmas with 40 nm lateral sizes is presented. The fabrication of shallow- and deep-etched quantum wires by selective crystallographic wet etching resulting in very narrow wires as small as 15 nm in width is presented. The free Cl$\sb2$ thermal etching of $\rm In\sb{0.53}Ga\sb{0.47}As/InP$ was developed, and its applications to quantum wire and quantum dot fabrication are presented. The fabricated structures showed good quality sidewalls comparable to wet etching techniques. Regrowth of InP was investigated on as-etched structures with and without SiO$\sb2$ masks. Finally, several processes of sample preparation for the selective area epitaxy of $\rm In\sb{x}Ga\sb{1-x}As/GaAs$ on submicron openings in SiO$\sb2$ masks for quantum wire fabrication were investigated. The inhomogeneity of the growth across an array of wires was investigated by spatially resolved luminescence and compared to a diffusion limited growth model.
Issue Date:1996
Rights Information:Copyright 1996 Panepucci, Roberto Ricardo
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9712393
OCLC Identifier:(UMI)AAI9712393

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