Quantitative spectroscopy of substitutional nitrogen in GaAs_{1 <i>x</i>}N_<i>x</i>epitaxial layers by local vibrational mode absorption

Abstract

Fourier transform infrared absorption measurements have been performed on thin films of GaAs1−xNx grown by metalorganic chemical vapour deposition or molecular beam epitaxy on semi-insulating GaAs substrates. The local vibrational mode absorption due to NAs is used to assess the substitutional nitrogen fraction. Based on a comparison with secondary ion mass spectroscopy and x-ray diffraction analysis, the calibration factor for the integrated absorption is derived. Quantitative determination of substitutional nitrogen is possible up to x ≈ 0.05, in epitaxial layers of thicknesses down to 10–100 nm.