Hg1−xCdxI220–25-&mgr;m-thick layers with a uniform composition in the range ofx=0.1–0.2were grown on CdTe substrates by vapor phase epitaxy (VPE). The growth was carried out using an&agr;-HgI2polycrystalline source at 200 °C and in the time range of 30–100 h. The layers were studied by scanning electron microscopy (SEM) and high resolution synchrotron x-ray topography (SXRT). The SEM and SXRT images ofHg1−xCdxI2VPE layers allow one to identify the defects affecting the layer structure. The two main types of structural defects in the layers are subgrain boundaries and densely spaced striations similar to those referred generally to as vapor grownHgI2bulk crystals. The effect of the growth time on these defects has been analyzed and on the basis of this it has been possible to growHg1−xCdxI2layers with low defect density.©1997 American Institute of Physics.