Citation
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 and Teweldeberhan, A.M. and Fahy, S.
(2008).
Local vibration modes and nitrogen incorporation in AlGaAs: N layers.
"Physica Status Solidi B-Basic Solid State Physics", v. 5
(n. 6);
pp. 2345-2348.
ISSN 0370-1972.
https://doi.org/10.1002/pssc.200778487.
Abstract
Raman scattering measurements in dilute AlGaAs:N films grown by plasma-assisted molecular beam epitaxy on (100) GaAs substrates reveal strong local vibration modes (LVM) associated to N complexes. The LVM observed frequencies between 325 and 540 cm–1 are in good agreement with density functional theory supercell calculations of AlnGa4–nN complexes (n = 1,2,3,4). We find that the observed LVMs correspond to all n values including Al4N. The LVMs spectra are resonant at energies around 1.85 eV. The values of the extended phonon frequencies of the ternary compound (GaAs and AlAs-like) reveal changes in the N distribution depending on the growth conditions: A transition from random- to nonrandom nitrogen distribution is observed upon increasing the growth temperature. Our results confirm the preferential bonding of N to Al in AlGaAs:N, due to the higher Al-N bond strength as compared to the Ga-N bond.
