Spectroscopic ellipsometry from 10 to 700 K.

The theory of these temperature effects on phonons is complicated [[9], [63]], but can be summarized as follows: An optical phonon has a finite lifetime on the order of a few 10 SP -12 sp s. Through an anharmonic perturbation of the Hamiltonian I H i SB 0 sb with self-energy , long-wavelength optical phonons can decay into two or more acoustic phonons. While the redshift of the main absorption peak of Ni at 4.8 eV with increasing temperature is similar to Si, Ge, and many other semiconductors, the temperature dependence of the broadening of this peak shows a very unusual behavior, see Figure 11. For metals and doped semiconductors, the temperature dependence of the Drude term is therefore dominated by the broadening parameter, which increases with temperature, similar to the broadening of band gaps and phonons shown in Figures 8 and 14. Keywords: cryostat; dielectric function; electron-phonon interaction; spectroscopic ellipsometry; temperature; windows EN cryostat dielectric function electron-phonon interaction spectroscopic ellipsometry temperature windows 117 135 19 08/09/22 20220501 NES 220501 1 Introduction Spectroscopic ellipsometry [[1]], [[2]], [[3]] is an optical reflection technique based on the polarization of electromagnetic waves. Cardona and S. Gopalan, "Temperature dependence of the band structure of semiconductors: electron-phonon interaction", in Progress in Electron Properties of Solids. [Extracted from the article]