Measurement of the absolute Raman cross section of the optical phonon in silicon

• Published in: Solid state communications Vol. 151; no. 7; pp. 553 - 556
• Main Authors: Aggarwal, R.L., Farrar, L.W., Saikin, S.K., Aspuru-Guzik, A., Stopa, M., Polla, D.L.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.04.2011; Elsevier
• Subjects: A. Semiconductors; B. Phonons; C. Inelastic light scattering; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Elemental semiconductors and insulators; Exact sciences and technology; Infrared and raman spectra and scattering; Lattice dynamics; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Phonon states and bands, normal modes, and phonon dispersion; Phonons and vibrations in crystal lattices; Physics; C. Inelastic light scattering; B. Phonons; A. Semiconductors; Optical phonons; Raman spectra; Semiconductor materials; Polarizability; Phonon mode; Density functional method; Polarized beams; Silicon; Calibration
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/j.ssc.2011.01.011

The absolute Raman cross section σ R S of the first-order 519 cm −1 optical phonon in silicon was measured using a small temperature-controlled blackbody for the signal calibration of the Raman system. Measurements were made with a 25-mil thick (001) silicon sample located in the focal plane of a 20-mm effective focal length (EFL) lens using 785-, 1064-, and 1535-nm CW pump lasers for the excitation of Raman scattering. The pump beam was polarized along the [100] axis of the silicon sample. Values of 1.0±0.2×10 −27, 3.6±0.7×10 −28, and 1.1±0.2×10 −29 cm 2 were determined for σ RS for 785-, 1064-, and 1535-nm excitation, respectively. The corresponding values of the Raman scattering efficiency S are 4.0±0.8×10 −6, 1.4±0.3×10 −6, and 4.4±0.8×10 −8 cm −1 sr −1.The values of the Raman polarizability | d | for 785-, 1064-, and 1535-nm excitation are 4.4±0.4×10 −15, 5.1±0.5×10 −15, and 1.9±0.2×10 −15 cm 2, respectively. The values of 4.4±0.4×10 −15 and 5.1±0.5×10 −15 cm 2 for | d | for 785- and 1064-nm excitation, respectively, are 1.3 and 2.0 times larger than the values of 3.5×10 −15 and 2.5×10 −15 cm 2 calculated by Wendel. The Raman polarizability | d | computed using the density functional theory in the long-wavelength limit is consistent with the general trend of the measured data and Wendel’s model. ► Raman cross section measurements made using 785-, 1064-, and 1535-nm pump lasers. ► Temperature-controlled blackbody used for the signal calibration of the Raman system. ► Raman polarizability computed in the static limit using the Quantum ESPRESSO package. ► The static value of the Raman polarizability is consistent with the measured data.