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

Abstract

GaAs 1− x N 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− x N x films with higher N incorporation. It is also evident that the N concentration in the GaAs 1− x N 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− x N x films ( x XRD⩽0.055).