Optical properties of RF-MBE grown AlGaAsN

Raman scattering and infrared absorption properties of RF-MBE grown AlGaAsN layers have been reported in order to investigate the microscopic lattice structures related with the nitrogen incorporation. Several new Raman modes of the Al-N bonds have been observed at 449, 500, and 650 cm(-1) in the Raman spectra of AlGaAsN (Al: 18-100%, N: similar to2%) instead of the mode of Ga-N bonds. The results strongly indicated that most of the N atoms form the Al-N bonds in the AlGaAsN layers. The infrared absorption spectra of the AlGaAsN have shown clearly that the TOAlN mode appears at 500 cm(-1). instead of the TOGaN mode that appeared at 469 cm(-1) in GaAsN. The peak shift and the broadening of the absorption peak of the TOAlN mode will be discussed in terms of variation of the statistical distributions of the AlnGa4-nN (n = 0, 1, 2, 3. 4) tetrahedral unit structures with increasing the Al amount.