Structural and vibrational properties of molecular beam epitaxy grown cubic (Al, Ga)N/GaN heterostructures

Abstract

The radio-frequency plasma-assisted molecular beam epitaxy of cubic AlyGa1−yN/GaN heterostructures on GaAs(001) substrates is reported. Rutherford backscattering spectroscopy, high resolution x-ray diffraction, and first-order micro-Raman spectroscopy measurements were used to characterize the structural and vibrational properties of the alloy epilayers. The Al content of the alloy is in the range from 0.07<x<0.20. X-ray diffraction reciprocal space maps demonstrate the good crystal quality of the cubic (Al, Ga)N/GaN films. The measured Raman shift of the TO phonon mode of the AlyGa1−yN alloy is in good agreement with theoretical calculations.