Novel Growth of Ingaas/Gaas Nanostructures by Molecular Beam
Abstract (Summary)This dissertation presents an extensive study of the epitaxial growth mechanism by a novel growth method. This novel growth method was developed at Utah State University and is a modification of the Stranski-Krastanov (S-K) growth mode. Our new growth method consists of a two-step process, low temperature growth and high temperature annealing. During low temperature growth, diffusion is minimized, resulting in the deposition of a pseudomorphic epilayer. During high temperature annealing, diffusion is induced from the pseudomorphic epilayer, resulting in the transformation of the epilayer into nanostructures. Benefits of this novel growth method are a significantly smaller segregation and suppressed intermixing due to the barrier wetting layer during sample growth. InGaAs nanostructures on GaAs(001) surfaces are examples of this new growth method. They were grown by molecular beam epitaxy (MBE) and analyzed using real-time reflection high energy electron diffraction (RHEED) and in situ scanning tunneling microscopy (STM). Our novel approach resulted in quantum dot chains and quantum dashes formed by annealing pseudomorphic layers of two different thicknesses of InGaAs on GaAs(001). These nanostructure shapes are different from those features formed by the conventional Stranski-Krastanov growth mode. The results indicate the potential to better understand nanostructures for future optoelectronic device applications.
School:Utah State University
School Location:USA - Utah
Source Type:Master's Thesis
Date of Publication:03/01/2009