Spontaneous Formation of Identical Collections of Nanostructures During Semiconductor Heteroepitaxy

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9402184 Drucker Research will be carried out to develop a fundamental understanding of the processes associated with direct epitaxial deposition to spontaneously form a collection of identical, defect free nanostructures during Ge/Si(100) heteroepitaxy. A unique combination of both in situ (low energy electron microscopy, scanning tunneling microscopy and ultrahigh vacuum scanning transmission electron microscopy) and ex situ (transmission electron microscopy) microscopy will be used to asses the size, uniformity, areal density and spatial distribution of these nanostructures. Tuning the size of uniform collections of dots will be investigated by varying the concentration of mobile adatoms (supersaturation) on the growth surface through changes in deposition parameters. The size of these nanostructures will be tuned through the Bohr radius in Ge, about 10 nm, to investigate the effects of quantum confinement. Use of direct epitaxial deposition allows formation of the target structures on a semiconductor surface, in situ and, most importantly, in a single step. %%% The primary goal of this program is to develop a fundamental-understanding of the epitaxial growth, processing, and properties of Ge/Si quantum dots so that they can be exploited in the realization of a variety of advanced electronic and photonic devices. An important feature of the program is the training of graduate and undergraduate students in a fundamentally and technologically significant area of materials and processing research. This research will contribute to improving the general performance of advanced devices and integrated circuits used in computing, information processing, and telecommunications. ***