Observation of a paramagnetic defect at the epitaxial Ge3N4/(111)Ge interface by electron spin resonance

A multifrequency electron spin resonance (ESR) study of Ge3N4/(111)Ge entities with nm thick epitaxial Ge3N4 layers, of subcritical thickness for mismatch relaxation, grown in a nitrogen plasma reveals the presence of an anisotropic paramagnetic interface center of trigonal symmetry. Building on the analysis of its specific ESR properties, including magnetic field angular mapping data and in the light of previous insight, the signal is tentatively ascribed to the interfacial ·Ge≡N3 center. The defect occurrence is discussed within the specific interface matching, without misfit dislocations. As an interfacial Ge dangling bond defect, it may operate as an inherent electrically detrimental trap.