Intrinsic germanium semiconductor specimens with various dislocation densities were quenched from high temperatures to introduce vacancies. The activation energy for diffusion and the diffusion coefficient were 1.2 to 1.3eV and 2exp[-1.2(eV)/kT]cm2/s. After annealing of quenched-in vacancies, copper atoms were introduced into the specimens by diffusion. By analysis of precipitating supersaturated copper atoms, the formation energy of a vacancy was found to be 1.9eV.

Experimental Determination of Diffusion and Formation Energies of Thermal Vacancies in Germanium. A.Hiraki: Journal of the Physical Society of Japan, 1966, 21[1], 34-41