Raman scattering of folded acoustic phonons in self-assembled Si/Ge dot superlattices

Tan, P. H.; Bougeard, D.; Abstreiter, G.; Brunner, K.
April 2004
Applied Physics Letters;4/5/2004, Vol. 84 Issue 14, p2632
Academic Journal
Self-assembled Si/Ge dot multilayers with small, uncorrelated dots fabricated by molecular beam epitaxy in the Stranski–Krastanov growth mode are studied by Raman scattering of folded longitudinal acoustic (FLA) modes. The FLA Raman spectra are analyzed and modeled with respect to mode frequencies and the spectral envelope of mode intensities. The deduced average superlattice properties are consistent with results from atomic force microscopy. The simple Rytov model used for Si/Ge layer structures reproduces very well the frequencies of the FLA modes up to 150 cm-1. The nonlinearity of phonon dispersion curves in bulk Si for large momenta, however, becomes important for modeling the higher frequencies of observed FLA modes up to 22nd order. The effective dot layer width and an activation energy for thermal intermixing of 2.1±0.2 eV are determined from the spectral envelopes of FLA mode intensities of as-grown and annealed Si/Ge dot multilayers. © 2004 American Institute of Physics.


Related Articles

  • Effect of Ca doping on the optical properties of La1.2Sr1.8Mn2O7. Her, J. L.; Liu, H. L.; Shen, C. H.; Liu, R. S.; Sheu, H. S. // Journal of Applied Physics;1/1/2006, Vol. 99 Issue 1, p013905 

    We present x-ray-diffraction, infrared reflectivity, and Raman-scattering measurements of La1.2(Sr1.8-xCax)Mn2O7 as a function of temperature and doping (x=0.0, 0.4, 0.6, and 0.8). At room temperature, x-ray-diffraction data show that the replacement of Sr ions with smaller Ca ions causes a...

  • Mode dispersion in the optical-phonon spectra of mixed crystals ZnS1− x Sex. Vinogradov, E. A.; Mavrin, B. N.; Novikova, N. N.; Yakovlev, V. A. // Physics of the Solid State;Oct2006, Vol. 48 Issue 10, p1940 

    The IR reflection and the Raman spectra of ZnS1− x Sex crystals (0≤ x ≤ 1) are measured. The mode dispersion of the solid solutions is found to deviate from that calculated using an isodisplacement model. The reasons behind this deviation are discussed. Two additional modes are...

  • Investigation of Phonon Band Gap, Heat Capacity and Raman Active Phonons in BaWO4 Crystal. Suda, J.; Zverev, P. G. // AIP Conference Proceedings;8/6/2010, Vol. 1267 Issue 1, p1150 

    The article presents a study conducted to examine phonon band gap, heat capacity and raman active phonons in BaWO4 crystal. It states that the phonon density of states (PDOS) and phonon-dispersion relations for BaWO4 crystal is calculated using the lattice dynamical calculations approach. It...

  • Does In-bonding delay GaN-segregation in GaInAsN? A Raman study. Tite, T.; Pagès, O.; Tournié, E. // Applied Physics Letters;12/13/2004, Vol. 85 Issue 24, p5872 

    The longitudinal (LO) and transverse (TO) optical Ga–N phonons of thick as-grown Ga1-yInyAs1-xNx/GaAs (001) layers with x∼3%–4%, i.e., just above the N-solubility limit xs∼2% in GaAs, and y up to 30% are studied by Raman scattering. We observe a three-mode behavior which...

  • Surface optical phonon and A1(LO) in ZnO submicron crystals probed by Raman scattering: Effects of morphology and dielectric coating. Liu, H. F.; Tripathy, S.; Hu, G. X.; Gong, H. // Journal of Applied Physics;Mar2009, Vol. 105 Issue 5, pN.PAG 

    The authors studied the surface optical phonon and A1(LO) in ZnO submicron crystals as well as ZnO single crystals with submicron surface structures by employing ultraviolet Raman scattering. The small variation in Raman frequency of A1(LO), when the growth condition is changed, is mainly caused...

  • Raman line shape of the A1 longitudinal optical phonon in GaN. Shi, L.; Ponce, F.A.; Menéndez, J. // Applied Physics Letters;5/3/2004, Vol. 84 Issue 18, p3471 

    High-resolution Raman measurements of the A1 longitudinal optical (LO) phonon in GaN reveal a complex line shape that can be explained in terms of the angular dispersion of LO phonons in this material. A simple geometrical model of the line shape makes it possible to extract the true anharmonic...

  • Temperature dependence of Raman scattering in AlInN. Jiang, L. F.; Kong, J. F.; Shen, W. Z.; Guo, Q. X. // Journal of Applied Physics;Jun2011, Vol. 109 Issue 11, p113514 

    A detailed investigation of temperature-dependent micro-Raman scattering has been carried out on AlInN films with different Al compositions (0-0.53). The observed phonon frequency downshift and linewidth broadening with increasing temperature can be well explained by a model taking into account...

  • Disorder effects on the Raman line shape in ZrO2. Falkovsky, L. A. // Journal of Experimental & Theoretical Physics;Jan2006, Vol. 102 Issue 1, p155 

    Experimental data obtained by Lughi and Clarke [5] are compared to the theory describing disorder effects on optical phonons. Sharpening and vanishing of the asymmetry of the Raman lines after annealing are attributed to a decrease in short-range disorder. The parameters of disorder (such as the...

  • Effects of high carrier densities on phonon and carrier lifetimes in Si by time-resolved anti-Stokes Raman scattering. Letcher, Jeffrey J.; Kang, Kwangu; Cahill, David G.; Dlott, Dana D. // Applied Physics Letters;6/18/2007, Vol. 90 Issue 25, p252104 

    The relaxation times T1 of nonequilibrium populations of elementary excitations in Si are studied by time-resolved Raman scattering using a subpicosecond pump-probe method. Incoherent anti-Stokes Raman scattering is used to monitor the decay of the nonequilibrium populations of holes and the...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics