TEM characterisation of GdN thin films

Abstract

The rare earth metal nitrides have been predicted to possess a wide range of electronic structures, ranging from ferromagnetic to half-metallic to semiconducting, which makes these materials attractive for a range of applications. In this study, GdN thin films were grown at room temperature on silicon and glass quartz substrates by thermally evaporating gadolinium metal in nitrogen atmospheres. A detailed microstructural characterisation of these films was carried out using a variety of techniques such as Transmission Electron Microscopy (TEM), Rutherford Backscattering Spectroscopy (RBS) and Energy Dispersive X-ray Spectrometry. TEM analysis indicated the films are nano-crystalline, with crystallite sizes being affected by the ionisation state of the nitrogen atmosphere used. Sources of the films' internal stress were discussed with a significant amount of oxygen absorption, identified by RBS, being a probable cause. Electron diffraction and energy dispersive X-ray studies found that GdN was the only phase present with oxygen uniformly distributed throughout the film.

Ion-Implanted Epitaxially Grown Gd2O3 on Silicon with Improved Electrical Properties

“…2 shows a very rough surface, and strong implantation effects are observed in the upper portion of the oxide layer, whereas the effects are comparatively weak near the substrate. These findings agree well with the stopping range of ions in matter (SRIM) implantation profile and with the structure of GdN reported by McKenzie et al 24 We observed the presence of an interfacial layer of thickness $ 7 nm which formed due to annealing after implantation. 25 The concentration of nitrogen in the interface between the SiO 2 and Gd 2 O 3 layer and the implanted areas of the Gd 2 O 3 oxide layer after sputter depth profiling is summarized in Table I.…”

Growth and oxidization stability of cubic Zr1−xGdxN solid solution thin films

“…A similar but much faster color change, probably due to a GdN film thicknesses of only $100 nm, has been reported in Ref. 41.…”

“…During the past ten years, it has been shown that rocksalt-structured GdN thin films can be grown both with physical vapor deposition techniques like reactive sputtering, [37][38][39][40] reactive thermal evaporation, [41][42][43] and molecular beam epitaxy, 44,45 but also with metal-organic chemical vapor deposition processes. 46,47 The intention has mainly been to deposit high quality films for investigations of their optical and magnetic properties.…”

Ion beam analysis of rare earth nitride thin films

“…XRD results revealed that the films have nanocrystalline (average crystallite size 10 nm) cubic GdN structure similar to the results observed by TEM [17]. Raman spectroscopy measurements show evidence of structural difference between GdN films [15].…”