Synthesis of Ge Nanostructures and Integration with Si
Abstract
This program focused on the synthesis of nanoparticles of metals and semiconductors, their properties, and the processes underlying their growth. We used a growth technique that we developed, namely buffer-layer-assisted growth (BLAG), and characterized the particles with transmission electron microscopy. We also used photoluminescence to study the Ge quantum dots. In BLAG, we condense a noninteractive buffer layer like Xe on a surface of choice at low temperature (any surface would do), and then use physical vapor deposition to deliver atoms of a second material of choice to the buffer. Those atoms are mobile, even at ~20 K, and they form small clusters. Subsequent warm-up and desorption of the buffer activates diffusion and aggregation so that the density and size of the nanoparticles that ultimately reach the substrate can be controlled. Under this program, we focused on understanding the mechanism underlying diffusion, how the particles aggregated, whether aggregation gave rise to compact or branched (ramified) structures and how the various parameters could be tuned to produce the desired sizes and distribution. We used TEM as the primary technique for quantifying the dependence of density and size on buffer layer thickness, warm-up rate, make up of the buffer (Xe, Ar, Kr), and the cluster material (Cu, Ag, Au, Co, Ni, Pd, Ge). The ultimate applications of this program would be in photonics (Ge, CdSe and other quantum dots), novel magnetics (device structures based on nanoscale magnets), and the understanding of material issues at the nanoscale.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 03, 2005
- Accession Number
- ADA441219
Entities
People
- John H. Weaver
Organizations
- University of Illinois Urbana–Champaign