An influence of grain boundaries in cadmium mercury telluride (CMT) CdxHg1-xTe films with a cellular or polycrystalline structure on the processes of segregation of point defects and generation and recombination of carriers under laser irradiation is studied. It is established that the intergrain path of CMT films, acting as electrical active interface, can fulfill the function of sinks, recombination inclusions as well as create potential barriers for recombination of the charge carriers. The laser-stimulated photosensitization of CMT films with a cellular structure, a jump in current-illumination characteristics (CICs) and anomalous injection-level dependence of the nonequilibrium carrier lifetime in CMT polycrystalline films at high illumination intensities are analyzed. (C) 2003 Elsevier Science B.V. All rights reserved.