Strain characterization of Hg_1-xFe_xSe-layers by electron spin resonance

HgSe:Fe layers are grown by molecular-beam-epitaxy and investigated by high-resolution-x-ray-diffraction and electron paramagnetic resonance. The lattice mismatch between HgSe and ZnTe leads to the formation of strain in the HgSe layers which is, however, relaxed in all samples investigated. Nevertheless, by Electron paramagnetic resonance a strain field in HgSe is found which occurs due to the difference in the thermal expansion coefficients of ZnTe and HgSe, respectively. We thus show that iron can be used as a local probe to measure strains in HgSe. We correlate the fine structure parameter necessary to describe the EPR spectra with the strain in the layers.