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

Teweldeberhan, A.M. and Stenuit, G. and Fahy, S. and Gallardo Velasco, Eva María and Lazic, Snezana and Calleja Pardo, José Manuel and Miguel-Sanchez, J. and Montes Bajo, Miguel and Hierro Cano, Adrián and Gargallo Caballero, Raquel and Fernández González, Alvaro de Guzmán and 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.

Description

Title: Resonant Raman-active localized vibrational modes in AlyGa{1-y}NxAs{1-x} alloys: Experiment and firstprinciples calculations
Author/s:
  • 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
Item Type: Article
Título de Revista/Publicación: Physical Review B
Date: April 2008
ISSN: 1098-0121
Volume: 77
Subjects:
Faculty: E.T.S.I. Telecomunicación (UPM)
Department: Ingeniería Electrónica
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

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.

More information

Item ID: 2716
DC Identifier: http://oa.upm.es/2716/
OAI Identifier: oai:oa.upm.es:2716
DOI: 10.1103/PhysRevB.77.155208
Official URL: http://prb.aps.org/toc/PRB/v77/i15
Deposited by: Memoria Investigacion
Deposited on: 06 Apr 2010 12:28
Last Modified: 20 Apr 2016 12:23
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