The ZnP2-Ge system and growth of single crystals of ZnGeP2
Abstract
The phase relations in the ZnP2-Ge join in the Zn-Ge-P system were determined. ZnGeP2 melts congruently at 1027 ± 3°C and undergoes a solid state transformation at 950 ± 5°C, in agreement with previous work. The low temperature phase, designated as αZnGeP2, has the tetragonal chalcopyrite structure, while the structure of the high temperature phase, designated as βZnGeP2, is unknown. Two eutectics are present: one between αZnGeP2 and Ge at 865 ± 4°C and 95 mol % Ge, and the other, between βZnGeP2 and ZnP2 at 970°C ± 4°C and 15 mol % Ge. Large crack- and bubble-free single crystals of ZnGeP2 can be grown by directional solidification without seeding, and the phase transition appears to be no impediment to the growth of large crystals. The extra absorption of a few cm-1 which exists between the band edge and 2μ has been shown to depend on crystal growth conditions. The source of the absorption, however, has not been identified. The absorption spectrum of a crystal grown from a liquid Bi-Pb alloy is compared with the spectra of crystals grown directly from ZnGeP2 melts.
- Publication:
-
Journal of Electronic Materials
- Pub Date:
- August 1973
- DOI:
- 10.1007/BF02660148
- Bibcode:
- 1973JEMat...2..445B