Sublimation Growth and Characterization of Erbium Nitride Crystals

• Published in: Crystal growth & design 2018-07, Vol.18 (7), p.3762-3766
• Main Authors: Al Atabi, Hayder A, Al Auda, Zahraa F, Padavala, B, Craig, M, Hohn, K, Edgar, James H
• Format: Article
• Language: English
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/acs.cgd.7b01543

Erbium nitride (ErN) is a rare earth nitride notable for its magnetic and optical properties. Here we report on its growth on a non-native substrate, tungsten foil, via physical vapor transport, and its characterization. The source material was erbrium metal that was converted to ErN by heating in nitrogen. Subsequently, it was sublimed to form the ErN crystals. The operating conditions were 1620–1770 °C and 150–330 Torr in pure nitrogen. The growth rate increased exponentially with temperature with an activation energy of 508 kJ/mol, and inversely with pressure. X-ray diffraction revealed that the ErN preferentially adopted a (100) orientation, the same as the dominant orientation of the tungsten sheet. The lattice constant was 4.853 Å. The crystal shapes and sizes were dependent on the temperature, as revealed by SEM and optical microscopy. The ErN crystals were highly faceted, bound by (100) and (111) crystal planes. The ErN compound deviated from stoichiometry: the Er:N atomic ratio ranged from 1:1.15 to 1:1.2 according to EDX and XPS elemental analysis. Raman spectra were in good agreement with theoretical predictions.