A free-carrier loss which was observed in a series of highly Si -doped quantum-well structures was explained in terms of a model for DX center formation which included Coulomb interactions. This explanation implied the existence of a strongly growth-dependent DX center energy. The data permitted the investigation of the DX center distribution between 0.214 and 0.249eV, and confirmed the occurrence of a considerably broadened DX center density of states (above 0.035eV).

J.M.Roberts, J.J.Harris, C.Roberts: Semiconductor Science and Technology, 1996, 11[3], 458-60