resumo
This study comprises a set of AlyInxGa1-x-yN thin films grown on GaN/sapphire substrate by MOVPE, with In content between 2 and 8% and Al between 21 and 38%. The thin films were optically characterized by means of UV-Visible total reflectance and mu-UV-Raman scattering, performed at room temperature. It is shown that the [Al]/[In] ration influences strongly the Reflectance spectra and a good correlation has been found between the reflectance maximum located at higher energy and the band gap predicted by Vegard's law for quaternary alloys. The Raman results indicate that the LO-AlGaN-like vibration mode is the dominated vibration in good agreement with the oscillator strength values obtained theoretically [12] for this alloys. It is shown how the influence of competing effects, such as composition and strain influences the frequency observed for the LO-AlGaN-like mode (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
palavras-chave
QUATERNARY; INXALYGA1-X-YN; WAVELENGTH; ALLOYS; GAP
categoria
Science & Technology - Other Topics; Materials Science; Physics
autores
Bola, AM; Correia, MR; Pereira, S; Gonzalez, JC; Lorenz, K; Alves, E; Barradas, N
nossos autores
Sérgio Manuel de Sousa Pereira
Investigador principalagradecimentos
This work was funded by FCT (No PTDC/FIS/65233/2006). A.Margarida Bola thanks I3N for her grant. The authors thank to Menno Kappers from Department of Materials Science and Metallurgy, University of Cambridge, U.K., for providing the samples for this study.