The Origin of Electrically Active Centers in a Near‐Coincidence Σ9 Grain Boundary in Germanium

The electronic defect states of a near‐coincidence Σ9 tilt grain boundary (GB) in germanium is characterized by means of deep level transient spectroscopy (DLTS). An energy level at (0.52 ± 0.02) eV below the conduction band of Ge is found for 1 × 10¹⁶ m⁻² defect states. The structure of this boundary, which contains GB dislocations (b = 1/9 [221] a), is further studied by high resolution electron microscopy (HREM). The dislocations are found to have many jogs (3 × 10¹⁶ m⁻²) which create dangling bonds. This finding may represent experimental evidence that the dangling bonds are at the origin of the electrical activity of the GB in Σ9 bicrystal.