Marked changes in metalorganic vapor-phase epitaxial layers of undoped CdHgTe on (100) GaAs were observed after prolonged storage at room temperature. The changes occurred in uniform n-type and non-uniform n-p layer structures, and were attributed to the out-diffusion of donors from the center of the layers. The  in situ  growth of a passivating layer of CdTe prevented these effects. Uniform n-type layers which were grown simultaneously onto (111) GaAs did not exhibit changes in electrical properties; even when they were not passivated with CdTe. It was concluded that the time-dependent properties were not associated with impurities, and were attributed to the diffusion of native donor defects and Hg acceptor vacancies. Their room-temperature diffusivities were estimated to be 7 x 10-14 and between 2 x 10-16 and 3 x 10-16cm2/s, respectively.

M.L.Young, J.Giess: Journal of Applied Physics, 1991, 69[10], 7173-7