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Title: Sculpting Semiconductor Heteroepitaxial Islands: From Dots to Rods

Abstract

In the Ge on Si model heteroepitaxial system, metal patterns on the silicon surface provide unprecedented control over the morphology of highly ordered Ge islands. Island shape including nanorods and truncated pyramids is set by the metal species and substrate orientation. Analysis of island faceting elucidates the prominent role of the metal in promoting growth of preferred facet orientations while investigations of island composition and structure reveal the importance of Si-Ge intermixing in island evolution. These effects reflect a remarkable combination of metal-mediated growth phenomena that may be exploited to tailor the functionality of island arrays in heteroepitaxial systems.

Authors:
; ;  [1];  [2]; ;  [3]; ;  [4];  [5];  [6];  [6];  [7]
  1. Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States)
  2. (United States)
  3. Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
  4. Department of Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706 (United States)
  5. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
  6. Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany)
  7. (Germany)
Publication Date:
OSTI Identifier:
20957730
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 98; Journal Issue: 10; Other Information: DOI: 10.1103/PhysRevLett.98.106102; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CRYSTAL GROWTH; GRAIN ORIENTATION; MAGNETIC ISLANDS; METALS; MORPHOLOGY; NANOSTRUCTURES; RODS; SEMICONDUCTOR MATERIALS; SILICON; SUBSTRATES

Citation Formats

Robinson, J. T., Cao, Y., Dubon, O. D., Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, Walko, D. A., Arms, D. A., Tinberg, D. S., Evans, P. G., Liddle, J. A., Rastelli, A., Schmidt, O. G., and Institute for Integrative Nanoscience, IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden. Sculpting Semiconductor Heteroepitaxial Islands: From Dots to Rods. United States: N. p., 2007. Web. doi:10.1103/PHYSREVLETT.98.106102.
Robinson, J. T., Cao, Y., Dubon, O. D., Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, Walko, D. A., Arms, D. A., Tinberg, D. S., Evans, P. G., Liddle, J. A., Rastelli, A., Schmidt, O. G., & Institute for Integrative Nanoscience, IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden. Sculpting Semiconductor Heteroepitaxial Islands: From Dots to Rods. United States. doi:10.1103/PHYSREVLETT.98.106102.
Robinson, J. T., Cao, Y., Dubon, O. D., Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, Walko, D. A., Arms, D. A., Tinberg, D. S., Evans, P. G., Liddle, J. A., Rastelli, A., Schmidt, O. G., and Institute for Integrative Nanoscience, IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden. Fri . "Sculpting Semiconductor Heteroepitaxial Islands: From Dots to Rods". United States. doi:10.1103/PHYSREVLETT.98.106102.
@article{osti_20957730,
title = {Sculpting Semiconductor Heteroepitaxial Islands: From Dots to Rods},
author = {Robinson, J. T. and Cao, Y. and Dubon, O. D. and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 and Walko, D. A. and Arms, D. A. and Tinberg, D. S. and Evans, P. G. and Liddle, J. A. and Rastelli, A. and Schmidt, O. G. and Institute for Integrative Nanoscience, IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden},
abstractNote = {In the Ge on Si model heteroepitaxial system, metal patterns on the silicon surface provide unprecedented control over the morphology of highly ordered Ge islands. Island shape including nanorods and truncated pyramids is set by the metal species and substrate orientation. Analysis of island faceting elucidates the prominent role of the metal in promoting growth of preferred facet orientations while investigations of island composition and structure reveal the importance of Si-Ge intermixing in island evolution. These effects reflect a remarkable combination of metal-mediated growth phenomena that may be exploited to tailor the functionality of island arrays in heteroepitaxial systems.},
doi = {10.1103/PHYSREVLETT.98.106102},
journal = {Physical Review Letters},
number = 10,
volume = 98,
place = {United States},
year = {Fri Mar 09 00:00:00 EST 2007},
month = {Fri Mar 09 00:00:00 EST 2007}
}
  • In the Ge on Si model heteroepitaxial system, metal patterns on the silicon surface provide unprecedented control over the morphology of highly ordered Ge islands. Island shape including nanorods and truncated pyramids is set by the metal species and substrate orientation. Analysis of island faceting elucidates the prominent role of the metal in promoting growth of preferred facet orientations while investigations of island composition and structure reveal the importance of Si-Ge intermixing in island evolution. These effects reflect a remarkable combination of metal-mediated growth phenomena that may be exploited to tailor the functionality of island arrays in heteroepitaxial systems.
  • In the Ge on Si model heteroepitaxial system, we show that metal patterns on the Si surface induce the assembly of deposited Ge atoms into highly ordered islands whose shapes are programmed by a combination of metal species and substrate orientation. The island shapes including truncated pyramids and nanorods are radically different from those grown on metal-free surfaces and arise by a process whereby intermixing between deposited Ge and substrate Si atoms from the onset of island formation facilitate the island shape evolution.
  • We propose a model to elucidate the self-organization process of islands in multilayer heteroepitaxial growth. The model is based on the preferential nucleation and growth of islands in regions of tensile strain in the total strain field on a spacer-layer surface induced both by embedded islands and by growing surface islands. Surface islands nucleate at the regions of tensile strain induced by embedded islands. The islands grow in size and induce increasingly large compressive strain on the spacer-layer surface. A surface island reaches a stable size after the total strain field around it becomes compressive. The model predicts that islandsmore » in successive layers not only form ordered columns but also show uniform distributions of island size and spacing, in agreement with experimental observations.« less
  • Heteroepitaxial Ge{sub 1-x}Mn{sub x} quantum dots (QDs) were grown on Si (001) by molecular beam epitaxial co-deposition, with x = 0 to 0.10, in order to explore the interaction between Mn content, surface morphological evolution, and magnetism. Morphological evolution typical of the Ge/Si (001) system was observed, where the effect of Mn on surface morphology is surprisingly minimal at low Mn content, with no obvious surface morphological indicators of second phase formation. As the Mn content increases, secondary phase formation becomes evident, appearing to heterogeneously nucleate on or within Ge QDs. Still higher Mn concentrations lead to extensive second phasemore » formation interspersed with an array of Ge QDs. Although ferromagnetism up to 220 K is observed, likely arising from intermetallic precipitates, there is no clear evidence for room-temperature ferromagnetism associated with a dilute magnetic solution phase.« less
  • Atomistic Monte Carlo simulations, coupling thermodynamic and kinetic effects, resolve a longstanding controversy regarding the origin of composition profiles in heteroepitaxial SiGe quantum dots. It is shown that profiles with cores rich in the unstrained (Si) component derive from near-equilibrium processes and intraisland diffusion. Profiles with cores rich in the strained (Ge) component are of nonequilibrium nature, i.e., they are strain driven but kinetically limited. They are shaped by the distribution of kinetic barriers of atomic diffusion in the islands. The diffusion pathways are clearly revealed for the first time. Geometrical kinetics play a minor role.