Quantum Growth
Structures and devices of nano-dimensions are expected to have unique and potentially useful properties. A very important issue for practical applications is structural stability. It is expected that quantum electronic effects such as quantum confinement and enhanced electron correlations, will be decisive in determining the structural stability of nano-structures.
We are investigating the factors that determine the morphological stability and structural relaxation of ultrathin metal films on semiconductors. The energy spectrum of these films is quantized in the direction perpendicular to the film and the precise location of the discrete energy levels will affect the overall stability of the film. For instance, Pb films on Si(111)7x7 seem to be especially stable at a thickness of seven atomic layers. Related factors for stability include the phase shifts of the quantum well states, lattice strain, and interplanar relaxation. We are investigating the quantum electronic properties and structural relaxations of these films using photoemission and LEED I-V. Our dream is to one day utilize our understanding of quantum growth to fabricate nanoparticles with narrow size distribution, or to create spatially ordered arrays of nano-particles.
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When the equivalent of three atomic layers of Pb is deposited onto Si(111)7x7, Pb preferably forms islands that are seven monolayers tall. (From W.B. Su et al. in Physical Review Letters). |
| Coworkers: | Anton Mans (graduate student) Hugo Dil (undergraduate student) |
| Collaborators: | Zhenyu Zhang (Theory) Ad Ettema |
| Quantum Growth Links: |
Mei-Yin Chou Michael Tringides TC-Chiang |
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