Uniaxial stress studies on the dominant nitrogen defect in silicon and germanium

The microstructure of the dominant nitrogen pair defect in silicon and germanium has been studied by uniaxial stress measurements on local vibrational modes ascribed to the pair. It is shown directly that the pair in germanium has a different structure than that of the well-known nitrogen pair in diamond. All the data are fully consistent with the recently proposed antiparallel model of the pair in both silicon and germanium.