We report on a study of disordering by the in-diffusion of a variety of Group IV and Group VI n-type impurities. Secondary ion mass spectroscopy, electrochemical C-V profiling, photoluminescence spectroscopy, and cathodoluminescence spectroscopy were used to determine the extent of interdiffusion, and the spatial distribution of impurities and native defects for impurity-induced disordering. In all cases, the n-type dopants enhance the Al-Ga interdiffusion coefficient over that due to an As overpressure of 2 atm alone. The Si-induced enhancement has been previously attributed to the change in Fermi level with doping and therefore should account for disordering using other n-type impurities. However, we observe important differences in the interdiffusion characteristics (diffusion rate, dopant profiles, energy and intensity of the deep-level emission) induced by Si or Ge, and that by S or Se. Whereas a strong correlation exists between the carrier concentration profile and the disordered regions in the Si-, Ge-, and Se-doped crystals, little direct correspondence is found for crystals doped with S. Instead, the disordering seems to be determined primarily by the presence of Group III vacancies, as is also the case in undoped crystals disordered by an As ambient alone. In addition, the deep level emission at 1.15 and 1.3 eV, which are associated with vacancy defects, correlates well with the extent of the Al-Ga interdiffusion.