TEMPERATURE-DEPENDENT MEASUREMENTS ON ZNSE HETEROSTRUCTURES BY HIGH-RESOLUTION X-RAY-DIFFRACTION

Thermally induced strain in ZnSe epitaxial layers on GaAs occurs due t o the different expansion coefficients of the single materials. This s train is directly investigated by high-resolution X-ray diffraction in the temperature range from 10 to 600 K. The strain is measured for a thick relaxed and a thin pseudomorphic layer. Furthermore, the lattice constants of ZnSe and GaAs bulk materials are determined at variable temperatures. It was observed that the thermal expansion is quite line ar for GaAs and ZnSe only in the temperature range from 250 to 600 K. The measured temperature-dependent lattice constants and the derived e xpansion coefficients are input parameters for a model to calculate th e thermally induced strain in the epitaxial layers. Good agreement cou ld be obtained between the experimental data and the model. (C) 1998 E lsevier Science B.V. All rights reserved.