Low temperature (1.7 K) reflectance and photoluminescence (PL) have been used to assess residual strain and impurities in molecular beam epitaxial (100) CdTe/Ge/Si and (100) ZnTe/Ge/Si. Both types of samples exhibit residual biaxial tensile thermal strain as expected from differences in previous thermal expansion data, but the measured magnitudes (0.72 × 10-3 for CdTe/Ge/Si and 1.5 × 10-3 for ZnTe/Ge/Si) are smaller than predicted. The results are consistent with either residual lattice mismatch stress or partial relaxation of the thermal strain during cooling. Residual acceptors in the CdTe include Cu and a frequently observed 49 meV level, whose PL peaks lack the previously reported linear polarization. However, a new series of linearly polarized bound exciton lines is reported in CdTe.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)