Correlation between Raman intensity of the N-related local vibrational mode and N content in GaAsN strained layers grown by MOVPE

GaAs_1-xN_x alloy films (0≤x≤0.055) grown on GaAs (0 0 1) substrates by metalorganic vapor phase epitaxy (MOVPE) using TBAs and DMHy as As and N precursors, respectively, have been investigated by Raman spectroscopy. It was found that, with incorporating N up to x = 0.055, a single N-related localized vibrational mode (LVM) is observed at around 468-475 cm^-1. We have investigated the N-related LVM Raman intensity (I_LVM) and frequency (ω_LVM) as a function of N concentration. Both the I_LVM and the ω_LVM were found to rise for the GaAs_1-xN_x films with higher N incorporation. It is also evident that the N concentration in the GaAs_1-xN_x grown films determined by Raman spectroscopy technique (x_Raman) exhibits a linear dependence on the N concentrations determined by the high resolution X-ray diffraction (HRXRD) (x_XRD). Our results demonstrate that the linear dependence of the x_Raman on the x_XRD provides a useful calibration method to determine the N concentration in dilute GaAs_1-xN_x films (x_XRD≤0.055).