Minimum energy path for the nucleation of misfit dislocations in Ge/Si(001) heteroepitaxy

Autor(es)

Trushin, O. ^[1] ; Maras, E. ^{[2, 3]} ; Stukowski, A. ^[4] ; Granato, E. ^{[5, 6]} ; Ying, S. C. ^[6] ; Jonsson, H. ^{[2, 7]} ; Ala-Nissila, T. ^{[2, 3, 6]}

Afiliação do(s) autor(es)

^[1] Russian Acad Sci, Yaroslavl Branch, Inst Phys & Technol, Yaroslavl 150007 - Russia

^[2] Aalto Univ, Sch Sci, Dept Appl Phys, FIN-00076 Espoo - Finland

^[3] Aalto Univ, Sch Sci, COMP Ctr Excellence, FIN-00076 Espoo - Finland

^[4] Tech Univ Darmstadt, Inst Mat Wissensch, D-64287 Darmstadt - Germany

^[5] Inst Natl Pesquisas Espaciais, Lab Associado Sensores & Mat, BR-12227010 Sao Jose Dos Campos, SP - Brazil

^[6] Brown Univ, Dept Phys, Box 1843, Providence, RI 02912 - USA

^[7] Univ Iceland, Fac Phys Sci, IS-107 Reykjavik - Iceland

• Tipo de documento: Artigo Científico
• Fonte: MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING; v. 24, n. 3 MAR 2016.
• Citações Web of Science: 1

Resumo

A possible mechanism for the formation of a 90 degrees misfit dislocation at the Ge/Si(0 0 1) interface through homogeneous nucleation is identified from atomic scale calculations where a minimum energy path connecting the coherent epitaxial state and a final state with a 90 degrees misfit dislocation is found using the nudged elastic band method. The initial path is generated using a repulsive bias activation procedure in a model system including 75 000 atoms. The energy along the path exhibits two maxima in the energy. The first maximum occurs as a 60 degrees dislocation nucleates. The intermediate minimum corresponds to an extended 60 degrees dislocation. The subsequent energy maximum occurs as a second 60 degrees dislocation nucleates in a complementary, mirror glide plane, simultaneously starting from the surface and from the first 60 degrees dislocation. The activation energy of the nucleation of the second dislocation is 30% lower than that of the first one showing that the formation of the second 60 degrees dislocation is aided by the presence of the first one. The simulations represent a step towards unraveling the formation mechanism of 90 degrees dislocations, an important issue in the design of growth procedures for strain released Ge overlayers on Si(1 0 0) surfaces, and more generally illustrate an approach that can be used to gain insight into the mechanism of complex nucleation paths of extended defects in solids. (AU)

• Processo FAPESP: 14/15372-3 - Dinâmica e defeitos topológicos em meios periódicos
• Beneficiário: Enzo Granato
• Linha de fomento: Auxílio à Pesquisa - Regular