Epitaxial growth of GdN on silicon substrate using an AlN buffer layer

We report on the epitaxial growth of the intrinsic ferromagnetic semiconductor GdN on Si (1 1 1) substrates buffered by a thick AlN layer forming a heteroepitaxial system with promise for spintronics Growth is achieved by depositing Gd in the presence of unactivated N-2 gas demonstrating a reactivity at the surface that is sufficient to grow near stoichiometric GdN only when the N-2 Gd flux ratio is at least 100 Reflection high-energy electron diffraction and X-ray diffraction show fully (1 1 1)-oriented epitaxial GdN films The epitaxial quality of the films is assessed by Rutherford backscattering spectroscopy carried out in random and channelling conditions Magnetic measurements exhibit a Curie temperature at 65 K and saturation magnetisation of 7 [mu(B)/Gd in agreement with previous bulk and thin-film data Hall effect and resistance data establish that the films are heavily doped semiconductors suggesting that up to 1% of the N sites are vacant (C) 2010 Elsevier BV All rights reserved