The II-VI ternary semiconductor alloy system Zn1−xCdxSe with 0 ≤ x ≤ 0.2 has important applications as the active material in blue-green light-emitting diodes and lasers. For the wavelength and temperature ranges over which these devices are designed to operate, a knowledge of the optical properties of the alloys is important. We report the results of spectroscopic ellipsometry measurements of the real part of the dielectric function e1 for Zn-rich Zn1−xCdxSe layers deposited epitaxially on (100) GaAs. We derive compact expressions that allow one to calculate accurate ε1 spectra from 1.5 eV, the low-energy limit of our ellipsometer, to E0 − 0.05 eV, where E0 is the fundamental bandgap energy, for any composition and temperature within the ranges 0 ≤ x ≤ 0.34 and 25 ≤ T < 260 °C. Furthermore, we expect that the results can also be extrapolated to cover the substrate temperature range typically used for the growth of these films (250−300 °C). Hence the results presented here are also useful in future real-time spectroscopic ellipsometry studies of Zn1−xCdxSe film growth.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Engineering (miscellaneous)
- Electrical and Electronic Engineering