Using polarized Raman spectroscopy, we examine different vibrational modes (i.e., Si–Si, Si–Ge, and Ge–Ge) in Si/Ge self-organized nanostructures. Here, we present unambiguous proof that multilayers of Ge nanometer-size, “dome-shaped” islands grown on a 〈100〉 Si substrate are nearly fully relaxed and that the built-in strain field is substantially localized in the surrounding Si matrix. In contrast, multilayers with “pyramid-shaped” islands do not show observable relaxation. The large strain in the Si layers of the multilayer dome samples correlates with the greater self-organization in these structures compared to the multilayer pyramid samples.
Polarized Raman scattering and localized embedded strain in self-organized Si/Ge nanostructures
B. V. Kamenev, H. Grebel, L. Tsybeskov, T. I. Kamins, R. Stanley Williams, J. M. Baribeau, D. J. Lockwood; Polarized Raman scattering and localized embedded strain in self-organized Si/Ge nanostructures. Appl. Phys. Lett. 15 December 2003; 83 (24): 5035–5037. https://doi.org/10.1063/1.1628403
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