X-RAY-ABSORPTION FINE-STRUCTURE OF ION-IMPLANTED HG0.79CD0.21TE SEMICONDUCTORS

The local environments around mercury atoms in the narrow-bandgap Hg0. 79Cd0.21Te semiconductor alloys have been deduced from extended x-ray absorption fine-structure (EXAFS) analysis. A nonlinear least-squares fitting was applied in order to determine the coordination number, the bond distances and the Debye-Waller factors for the nearest and the n ext-nearest neighbours around the Hg atom. While ordering has been fou nd for the first coordination shell which consists of four tetrahedral ly coordinated Te atoms at 0.280 nm, the next-neighbour shell (consist ing of 12 cations) is split into two peaks at the bond lengths of 0.45 4 nm for HS-Cd and 0.459 nm for Hg-Hg. Local structure parameters for Kr- and Xe-ion-implanted Hg0.79Cd0.21Te crystals are also analysed.