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X-Ray and Photoluminescence Characterization of a Strain-Free GaAs-on-Si Structure Formed by Annealing under Ultrahigh Pressure

Characteristics of strain-free GaAs-on-Si structures formed by annealing under ultrahigh pressure were investigated by X-ray diffraction (XRD) analysis and photoluminescence (PL) measurement. It was found that a strain-free GaAs film was formed on a Si substrate without serious degradation of the optical and crystallographical properties of the film. It was also found that no additional strain or defects were generated during PL measurement at 77 K. Next, the strain-free GaAs-on-Si structure was reannealed at atmospheric pressure, and variation of the strain was investigated. It was found in this experiment that the strain in the GaAs film increased rapidly in the first 5 min of reannealing but within 20 to 30 min it reached to a constant value which was determined by the reannealing temperature. Finally, both XRD and PL data were compared and an intensity result on the depth distribution of strain in a GaAs film was derived.