Optical and structural properties of epitaxially lifted-off GaAs films

Abstract

The influence of the layer thickness on the optical and structural properties of the epitaxially lifted-off (ELO) thin films has been studied. The ELO films bonded to Si, InP, and GaAs substrates have also been compared. The structure was characterized by high-resolution double-crystal x-ray diffraction and the optical properties were measured by the temperature-dependent photoluminescence spectroscopy. A biaxial compressive strain was observed for the samples bonded to Si with a buffer layer thinner than 1000 nm. Due to different thermal expansion coefficient between the grafted thin film and the host substrate, the emission spectra of the quantum wells of the lifted-off thin films are redshifted compared to the as-grown sample. The amount of the redshift is larger for thinner films. (C) 1998 American Institute of Physics.