| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1790569 | Journal of Crystal Growth | 2014 | 4 Pages |
•PPDs only observed in CdTe compounds were annealed under Cd overpressure.•Star-shaped PPDs are results of exothermic reaction between Cd and Te.•Star-shaped PPDs are just structural defects.•Cadmium in-diffusion process in annealing occurs via Cd vacancies.
The origin and nature of star-shaped prismatic punching defects (PPDs) were analyzed by white-beam X-ray diffraction topography (WBXDT) and photoluminescence (PL) measurements. PPDs were observed in CdTe-based compounds that had Te-rich secondary phase defects and were annealed only under Cd overpressure. The evolutional features of the PPDs during annealing were similar to those of a diffusion process, that is, the in-diffusion of Cd vapor via Cd vacancies. PL mapping around the PPDs reveals that the stoichiometry of PPDs is the same as that of a normal matrix, and that PPDs are just structural defects with non-radiative emission induced by the exothermic reaction between Cd and Te. We find that Te-rich secondary phase defects can be removed without the generation of star-shaped PPDs, if the exothermic reaction rate can be slowed down to reduce the thermal gradient between the Te-rich region and the surrounding matrix.
