Effect of Lattice Mismatch on HgCdTe LPE Film Surface Morphology

A new type of crystal defect, which we call a rough structure, is reported in this work. The rough structure appears in large lattice mismatch regions whereas a normal surface appears in the regions where there is a small lattice mismatch on the same substrate. Experiments proved that under normal liquid-phase epitaxy growth conditions, the appearance of a rough structure is related to the lattice mismatch between the substrate and the film. Statistical data indicated that for Hg 1− x Cd x Te films with different Cd compositions x , a rough structure appeared on the film surface when the lattice mismatch was outside the range of 0.02–0.11%. The rough structure may result from the misfit dislocations resulting from strain relaxation. When there was a small surface crystal orientation deviation from (111), dense growth ripples appeared instead of the rough structure. A super-flat surface sometimes appeared inside the rough structure regions.