Evaluation of growth temperature, refractive index, and layer thickness of thin ZnTe, MnTe, and CdTe films by in situ visible laser interferometry

Abstract

The experimental procedure and the results of in situ determination of growth temperatures, refractive indices at growth temperatures, and thicknesses of ZnTe, cubic MnTe, and CdTe thin films grown by molecular beam epitaxy (MBE) are reported. Visible laser interferometry with He-Ne laser 0.6328-μm light has been applied in the performed experiments. A 290-μm-thick plane-parallel GaP wafer polished to an optical finish on both sides has been used as a growth temperature calibration standard. The exemplary substrate temperature calibration curves, as well as the data gained at dynamic thermal conditions are presented and discussed. The following numerical values concerning refractive indices n at elevated temperatures have been evaluated from experimental data for the MBE grown films: n (286°C)ZnTe=2.51, n (175°C) ZnTe=2.49, n(286°C)cubic MnTe=3.26, and the extinction coefficient k (286°C)CdTe=0.23.