Lattice parameter in GaNAs epilayers on GaAs: Deviation from Vegard’s law

Abstract

The N content and lattice parameter of GaNxAs1−xepilayers on GaAs (0<x<0.03) were determined by secondary ion mass spectroscopy and x-ray diffraction measurements, respectively. A significant deviation of the lattice parameter variation in GaNxAs1−x from Vegard’s law between GaAs and cubic GaN was observed, which leads to overestimation of the nitrogen content by up to 30% for x⩽2.5%. The physical origin of this negative deviation is discussed.