Dislocation Photoluminescence in Silicon and Germanium

Dislocation photoluminescence (DPL) is studied at 4.2K in plastically deformed germanium single crystals containing predominantly 60fl dislocations of “relaxed” morphology. The DPL spectra were deconvolved into Gaussian (Gm) lines of two groups over the range 0.5-0.6 eV. One of these lines corresponds to the radiation of 60fl dislocations with the equilibrium stacking fault width F0. To clarify the origin of the other Gm lines, the effect of both the dislocation density ND, ranging from106 to 109 cm-2, and the annealing at temperatures above 600flC on the intensity of Gm lines was investigated. The origin of different lines in the DPL spectra of germanium and silicon is discussed.