Molecular-beam epitaxy and lattice parameter of GaNxSb1-x: deviation from Vegard's law for x > 0.02.

The N content of a series of GaNSb samples grown by molecular-beam epitaxy is investigated using high-resolution x-ray diffraction (HRXRD) and secondary-ion mass spectrometry. The N contents determined by the two methods agree well at lower N compositions (x < 0.01), and deviate significantly at larger N contents (x > 0.02). Analysis of the HRXRD-determined lattice constant using Vegard's law, underestimates the N content for high N compositions. The underestimation is found to be up to 24% for x = 0.03. The variation of the lattice parameter with N content is modelled by considering the influence of the density of the interstitial N-Sb complex rising with increasing N content. [ABSTRACT FROM AUTHOR]