Determination of surface lattice strain in ZnTe epilayers on (100)GaAs by ion channeling and reflectance spectroscopy

We report on the direct measurements of surface lattice strain in ZnTe epitaxial layers on {100}GaAs substrates by ion channeling Rutherford backscattering spectrometry and low-temperature (10 K) reflectance spectroscopy measurements. The measured ZnTe strain is the superposition of the expected thermal (tensile) strain and a thickness-dependent residual compressive strain. Our data indicate that the removal of this residual strain is slower than the rate predicted by the equilibrium theory, following an apparent h-1/2 power-law dependence on the epilayer thickness h, above approximately 100 nm.