Resonant Raman-active localized vibrational modes in AlyGa{1-y}NxAs{1-x} alloys: Experiment and firstprinciples calculations

Teweldeberhan, A.M.; Stenuit, G.; Fahy, S.; Gallardo Velasco, Eva María; Lazic, Snezana; Calleja Pardo, José Manuel; Miguel-Sanchez, J.; Montes Bajo, Miguel; Hierro Cano, Adrián; Gargallo Caballero, Raquel; Fernández González, Alvaro de Guzmán y Muñoz Merino, Elias (2008). Resonant Raman-active localized vibrational modes in AlyGa{1-y}NxAs{1-x} alloys: Experiment and firstprinciples calculations. "Physical Review B", v. 77 (n. 15); pp.. ISSN 1098-0121. https://doi.org/10.1103/PhysRevB.77.155208.

Descripción

Título: Resonant Raman-active localized vibrational modes in AlyGa{1-y}NxAs{1-x} alloys: Experiment and firstprinciples calculations
Autor/es:
  • Teweldeberhan, A.M.
  • Stenuit, G.
  • Fahy, S.
  • Gallardo Velasco, Eva María
  • Lazic, Snezana
  • Calleja Pardo, José Manuel
  • Miguel-Sanchez, J.
  • Montes Bajo, Miguel
  • Hierro Cano, Adrián
  • Gargallo Caballero, Raquel
  • Fernández González, Alvaro de Guzmán
  • Muñoz Merino, Elias
Tipo de Documento: Artículo
Título de Revista/Publicación: Physical Review B
Fecha: Abril 2008
Volumen: 77
Materias:
Escuela: E.T.S.I. Telecomunicación (UPM)
Departamento: Ingeniería Electrónica
Licencias Creative Commons: Reconocimiento - Sin obra derivada - No comercial

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Resumen

The localized vibrational modes associated with substitutional aluminium and nitrogen atoms in AlyGa1−yNxAs1−x have been studied within first-principles density functional theory using a supercell approach. Localized vibrational modes related to N-AlmGa4−m (1≤m≥4) complexes have been identified, which reveal the formation of N-Al4 units well above random abundance, in qualitative agreement with a large calculated value (391 meV) of the Al-N bond formation energy. We determine the resonant Raman-active modes from the selection rule obtained by calculating the electron-phonon coupling strength and optical transition matrix elements and compare them with resonant Raman spectroscopy measurements. The localized modes from Raman scattering measurements with frequencies around 325, 385, 400, 450, 500, and 540 cm−1 are found to be in good agreement with the calculated modes (326, 364, 384, 410, 456, 507, and 556 cm−1). The modes are classified as follows: the two modes at 326 and 556 cm−1 belong to the N-AlGa3 configuration; there are three modes which belong to N-Al2Ga2 with frequencies at 326, 364, and 507 cm−1; the N-Al3Ga configuration gives rise to modes whose frequencies are 384 and 456 cm−1; and the mode at a frequency of 410 cm−1 belongs to the N-Al4 complex. The comparison of line intensities from samples before and after rapid thermal annealing allows us to experimentally distinguish vibrational modes associated with different clusters, in agreement with the theoretical assignments.

Más información

ID de Registro: 2716
Identificador DC: http://oa.upm.es/2716/
Identificador OAI: oai:oa.upm.es:2716
Identificador DOI: 10.1103/PhysRevB.77.155208
URL Oficial: http://prb.aps.org/toc/PRB/v77/i15
Depositado por: Memoria Investigacion
Depositado el: 06 Abr 2010 12:28
Ultima Modificación: 20 Abr 2016 12:23
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