Temperature dependence of strain-phonon coefficient in epitaxial Ge/Si(001): A comprehensive analysis

We investigate the temperature dependence of the Ge Raman mode strain-phonon coefficient in Ge/Si heteroepitaxial layers. By analyzing the temperature-dependent evolution of both the Raman Ge& x2500;Ge line and of the Ge lattice strain, we obtain a linear dependence of the strain-phonon coefficient as a function of temperature. Our findings provide an efficient method for capturing the temperature-dependent strain relaxation mechanism in heteroepitaxial systems. Furthermore, we show that the rather large variability reported in the literature for the strain-phonon coefficient values might be due to the local heating of the sample due to the excitation laser used in mu-Raman experiments.