Structure study of Hg1-xCdxTe-HgTe superlattice and CdTe/ZnTe/GaAs heterojunctions

A rocking curve of Hg1-xCdxTe-HgTe superlattice sample grown by molecular b eam epitaxy (MBE) was determined by X-ray diffraction around the (0 0 2) Br agg reflection, which shows primarily the superlattice structure property. A simulation curve was calculated using the dynamic theory. There is a good agreement between the two curves, and the period length, HgTe well thickne ss, and the Hg1-xCdxTe barrier thickness measured from the experimental cur ve is consistent with that calculated from the simulation curve. The CdTe/Z nTe double buffer layers were employed instead of the CdTe single buffer la yer. The micrographs of cross-sections of the Hg1-xCdxTe-HgTe superlattice and the heterojunctions between the bibuffer layers and substrate were demo nstrated by transmission electron microscopy (TEM), and the feature and dis tribution of mismatch dislocation at the CdTe/ZnTe/GaAs heterojunctions wer e also analyzed. It is clearly shown that the CdTe/ZnTe double buffer layer s are more effective than the single CdTe buffer layer for some defects. Th e high resolution bright field micrograph of the superlattice cross-section shows the smoothness of the interface, as well as that the average superla ttice period length is similar to the one from X-ray diffraction. (C) 1999 Elsevier Science B.V. All rights reserved.