title: Thermodynamics of coherently-strained GexSi1-x nanocrystals on Si(001): alloy composition and island formation.
abstract: We determined the enthalpic and entropic contributions to the thermodynamics of coherently strained nanocrystals grown via deposition of pure Ge on Si(001) surfaces at 600 and 700 degrees C by analyzing their composition profile and local strain. We found that the free energy associated with the entropy of mixing, which drives GexSi1-x alloy formation, was significantly larger than the relaxation enthalpy that produces the islands. Thus, entropy plays a significant role in the evolution of the size and shape of the islands during growth through the strong thermodynamic drive to form an alloy.
authors.affiliation: Hewlett-Packard Laboratories, 1501 Page Mill Rd., Palo Alto, California 94304, USA. gmedeiros@lnls.br
authors.forename: Gilberto
authors.initials: G
authors.lastname: Medeiros-Ribeiro
authors.forename: R Stanley
authors.initials: RS
authors.lastname: Williams