Strain effect on the instability of island formation in submonolayer heteroepitaxyMaozhi Li1, Yugui Yao2, Biao Wu2, Zhenyu Zhang3, 4 and Enge Wang2
1 Department of Physics, Renmin University of China - Beijing 100872, China
2 Institute of Physics, Chinese Academy of Sciences - P.O. Box 603, Beijing 100190, China
3 Materials Science and Technology Division, Oak Ridge National Laboratory - Oak Ridge, TN 37831, USA
4 Department of Physics and Astronomy, The University of Tennessee - Knoxville, TN 37996, USA
received 10 November 2008; accepted in final form 9 March 2009; published April 2009
published online 14 April 2009
A theoretical model is developed to study the strain effect on the instability of island formation in submonolayer heteroepitaxy in both thermodynamic and growth kinetic regimes. By using the linear-stability analysis, the elastic energy change of a circular island is derived. Combined with a rate equation theory, the interplay between growth kinetics and strain effect on the shape instability is analyzed and illustrated with the constructed morphological phase diagrams. Critical island sizes beyond which islands grow unstable are also derived and can be used to estimate the energy parameters. Well-defined scaling properties are also obtained for the shape instability.
68.35.Gy - Mechanical properties; surface strains.
81.15.Aa - Theory and models of film growth.
68.35.Md - Surface thermodynamics, surface energies.
© EPLA 2009