We report persistent photoconductivity in Mg-doped GdN thin films grown by molecular beam epitaxy. Temperature-dependent measurements were carried out in the time and frequency domains to probe the nature of Mg impurities in GdN. The results reveal an initial fast decay followed by a slow persistent photoconductivity. The magnitude of the photoconductivity as well as the characteristic fast- and slow-decay times was found to decrease systematically with increasing the Mg-doping level. Our experimental results suggest that Mg impurities in epitaxial GdN thin films act as acceptor-like centres. Interestingly they also show that the incorporation of Mg result in a significant decrease in the concentration of nitrogen vacancies, as is demonstrated also to be in agreement with an ab initio calculation.
Experimental and ab initio study of Mg doping in the intrinsic ferromagnetic semiconductor GdN
C.-M. Lee, J. Schacht, H. Warring, H. J. Trodahl, B. J. Ruck, S. Vézian, N. Gaston, F. Natali; Experimental and ab initio study of Mg doping in the intrinsic ferromagnetic semiconductor GdN. J. Appl. Phys. 21 March 2018; 123 (11): 115106. https://doi.org/10.1063/1.5020081
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